R. C. Bray

Publication List Details

Period

1999 - 2001

Number

144

Co-Authors

Reactions of dimethylsulfoxide reductase from Rhodobacter capsulatus with dimethyl sulfide and dimethyl sulfoxide: Complexities revealed by conventional and stopped-flow spectrophotometry (1999)

Adams, B., Smith, A. T., Bailey, S., McEwan, A. G., Bray, R. C.

Improved assays for the molybdenum enzyme dimethylsulfoxide reductase (DMSOR) with dimethyl sulfoxide (DMSO) and with dimethyl sulfide (DMS) as substrates are described. Maximum activity was observed...

Reactions of dimethylsulfoxide reductase from Rhodobacter capsulatus with dimethyl sulfide and dimethyl sulfoxide: Complexities revealed by conventional and stopped-flow spectrophotometry (1999)

Adams, B., Smith, A. T., Bailey, S., McEwan, A. G., Bray, R. C.

Improved assays for the molybdenum enzyme dimethylsulfoxide reductase (DMSOR) with dimethyl sulfoxide (DMSO) and with dimethyl sulfide (DMS) as substrates are described. Maximum activity was observed...

MÖSSBAUER SPECTROSCOPY OF THE IRON-SULFUR PROTEINS*

Johnson, C. E., Bray, R. C., Cammack, R., Hall, D. O.

The Mössbauer spectra of 57Fe in two plant ferredoxins (from spinach and Euglena) and in xanthine oxidase have been measured at a series of temperatures and magnetic fields, and are found to be...

Information from e.p.r. spectroscopy on the iron-sulphur centres of the iron-molybdenum protein (aldehyde oxidoreductase) of Desulfovibrio gigas.

Bray, R C, Turner, N A, Le Gall, J, Barata, B A, Moura, J J

E.p.r. spectra of reduced iron-sulphur centres of the aldehyde oxidoreductase (iron-molybdenum protein) of Desulfovibrio gigas were recorded at X-band and Q-band frequencies and simulated. Results...

Use of rosy mutant strains of Drosophila melanogaster to probe the structure and function of xanthine dehydrogenase.

Hughes, R K, Doyle, W A, Chovnick, A, Whittle, J R, Burke, J F, Bray, R C

The usefulness in structure/function studies of molybdenum-containing hydroxylases in work with rosy mutant strains of Drosophila melanogaster has been investigated. At least 23 such strains are...

Isolation, in the intact state, of the pterin molybdenum cofactor from xanthine oxidase.

Deistung, J, Bray, R C

A procedure is described for isolation of the pterin molybdenum cofactor, in the active molybdenum-containing state, starting from purified milk xanthine oxidase. The method depends on the use of...

The isolation of demolybdo xanthine oxidase from bovine milk.

Ventom, A M, Deistung, J, Bray, R C

It was deduced many years ago from indirect evidence that demolybdo xanthine oxidase is present in normal bovine milk. This has now been confirmed by isolation of this enzyme form by a method based...

X-ray-absorption and electron-paramagnetic-resonance spectroscopic studies of the environment of molybdenum in high-pH and low-pH forms of Escherichia coli nitrate reductase.

George, G N, Turner, N A, Bray, R C, Morpeth, F F, Boxer, D H, Cramer, S P

Previous e.p.r. work [George, Bray, Morpeth & Boxer (1985) Biochem. J. 227, 925-931] has provided evidence for a pH- and anion-dependent transition in the structure of the Mo(V) centre of Escherichia...

Information from e.x.a.f.s. spectroscopy on the structures of different forms of molybdenum in xanthine oxidase and the catalytic mechanism of the enzyme.

Turner, N A, Bray, R C, Diakun, G P

X-ray spectroscopy was used to provide further information on the structure of the molybdenum centre of xanthine oxidase. Earlier work was confirmed and two states of the enzyme, not reported on by...

Studies by electron-paramagnetic-resonance spectroscopy of the environment of the metal in the molybdenum cofactor of molybdenum-containing enzymes.

Hawkes, T R, Bray, R C

The molybdenum cofactor prepared by denaturing xanthine oxidase by heat treatment or other methods was partially purified by anaerobic gel filtration in the presence of sodium dithionite, with little...

Electron-paramagnetic-resonance spectroscopy studies on the dissimilatory nitrate reductase from Pseudomonas aeruginosa.

Godfrey, C, Greenwood, C, Thomson, A J, Bray, R C, George, G N

Preparations of nitrate reductase in the resting state from Pseudomonas aeruginosa exhibit an Mo(V) e.p.r. signal. Progressive reduction of the enzyme results at first in the intensification and then...

Complexes with halide and other anions of the molybdenum centre of nitrate reductase from Escherichia coli.

George, G N, Bray, R C, Morpeth, F F, Boxer, D H

The interconversion of nitrate reductase from Escherichia coli between low-pH and high-pH Mo(V) e.p.r. signal-giving species was re-investigated [cf. Vincent & Bray (1978) Biochem. J. 171, 639-647]....

Comparison of the processes involved in reduction by the substrate for two homologous flavocytochromes b2 from different species of yeast.

Capeillère-Blandin, C, Barber, M J, Bray, R C

A detailed study of the electron exchanges involved between FMN and haem b2 groups within flavocytochrome b2 of yeast Hansenula anomala (H-enzyme) was performed. The results were compared with those...

The molybdenum iron-sulphur protein from Desulfovibrio gigas as a form of aldehyde oxidase.

Turner, N, Barata, B, Bray, R C, Deistung, J, Le Gall, J, Moura, J J

The molybdenum iron-sulphur protein originally isolated from Desulfovibrio gigas by Moura, Xavier, Bruschi, Le Gall, Hall & Cammack [(1976) Biochem. Biophys. Res. Commun. 72, 782-789] has been...

Investigation by electron paramagnetic resonance spectroscopy of the molybdenum centre of respiratory nitrate reductase from Paracoccus denitrificans.

Turner, N, Ballard, A L, Bray, R C, Ferguson, S

The molybdenum centre of respiratory nitrate reductase from Paracoccus denitrificans has been investigated by e.p.r. spectroscopy of Mo(V). In common with the centres of the analogous enzymes from...

Studies by electron-paramagnetic-resonance spectroscopy of the molybdenum centre of spinach (Spinacia oleracea) nitrate reductase.

Gutteridge, S, Bray, R C, Notton, B A, Fido, R J, Hewitt, E J

The molybdenum centre of spinach (Spinacia oleracea) nitrate reductase has been investigated by e.p.r. spectroscopy of molybdenum(V) in reduced forms of the enzyme. The resting enzyme gives no...

The effect of pH on the exchangeability with deuterium of protons coupled to molybdenum(V) in the active and the desulpho forms of xanthine oxidase.

Malthouse, J P, Bray, R C

The effect of pH variation on the exchangeability with deuterium of protons strongly coupled to Mo(V) in the active and desulpho forms of xanthine oxidase was studied by e.p.r. and rapid freezing, in...

Detection by low-temperature magnetic circular-dichroism spectroscopy of optical absorption bands due to molybdenum (V) in the form of xanthine oxidase giving the Desulpho Inhibited e.p.r. signal.

Peterson, J, Godfrey, C, Thomson, A J, George, G N, Bray, R C

The magnetic circular-dichroism (m.c.d.) spectra in the temperature range 1.5-100 K and the electronic absorption spectra at 4.2 and 295 K were measured for a number of desulpho xanthine oxidase...

The structure of the inhibitory complex of alloxanthine (1H-pyrazolo[3,4-d]pyrimidine-4,6-diol) with the molybdenum centre of xanthine oxidase from electron-paramagnetic-resonance spectroscopy.

Hawkes, T R, George, G N, Bray, R C

Studies were carried out on the inhibitory complex of alloxanthine (1H-pyrazolo[3,4-d]pyrimidine-4,5-diol) with xanthine oxidase, in extension of the work of Williams & Bray [Biochem. J. (1981) 195,...

Quantitative transfer of the molybdenum cofactor from xanthine oxidase and from sulphite oxidase to the deficient enzyme of the nit-1 mutant of Neurospora crassa to yield active nitrate reductase.

Hawkes, T R, Bray, R C

An assay method is described for measurement of absolute concentrations of the molybdenum cofactor, based on complementation of the defective nitrate reductase ('apo nitrate reductase') in extracts...

Formamide as a substrate of xanthine oxidase.

Morpeth, F F, George, G N, Bray, R C

Formamide is a substrate of xanthine oxidase. At pH 8.2 and 1.14 mM-O2, Vmax.(app.) is 3.1 s-1 and Km (app.) is 0.7 M. Mo(V) e.p.r. signals obtained by treating the enzyme with formamide were...

Equilibria amongst different molybdenum (V)-containing species from sulphite oxidase. Evidence for a halide ligand of molybdenum in the low-pH species.

Bray, R C, Gutteridge, S, Lamy, M T, Wilkinson, T

The interaction of chloride, fluoride and phosphate ions with the molybdenum centre of sulphite oxidase in the pH range 6.2 to 9.6 has been studied by e.p.r. of Mo(V) in the enzyme reduced by...

Studies by e.p.r. spectroscopy of carbon monoxide oxidases from Pseudomonas carboxydovorans and Pseudomonas carboxydohydrogena.

Bray, R C, George, G N, Lange, R, Meyer, O

E.p.r. spectra were obtained at 8-120 K for carbon monoxide oxidases isolated from the carboxydotrophic bacteria Pseudomonas carboxydovorans and Pseudomonas carboxydohydrogena. Spectra from the two...

Studies by electron-paramagnetic-resonance spectroscopy of the molybdenum centre of aldehyde oxidase.

Bray, R C, George, G N, Gutteridge, S, Norlander, L, Stell, J G, Stubley, C

Molybdenum(V) e.p.r. spectra from reduced forms of aldehyde oxidase were obtained and compared with those from xanthine oxidase. Inhibited and Desulpho Inhibited signals from aldehyde oxidase were...

Purification and properties of nitrogenase in ethylene glycol at sub-zero temperatures.

Tsopanakis, A D, Bray, R C, Smith, B E

Both the protein components Kp1 and Kp2 of nitrogenase from Klebsiella pneumoniae were found to be stable in aq. 50% (v/v) ethylene glycol at +30 degrees C or below. At -20 degrees C in this medium...

Rapid type 2 molybdenum(V) electron-paramagnetic resonance signals from xanthine oxidase and the structure of the active centre of the enzyme.

Malthouse, J P, Gutteridge, S, Bray, R C

Rapid type 2 molybdenum(V) e.p.r. signals from reduced functional xanthine oxidase have been further investigated. These signals, which show strong coupling of two protons to molybdenum, have been...

Oxygen-17 splitting of the very rapid molybdenum(V) e.p.r. signal from xanthine oxidase. Rate of exchange with water of the coupled oxygen atom.

Gutteridge, S, Bray, R C

Studies have been carried out of effects of 17O substitution on a Mo(V) e.p.r. signal from xanthine oxidase, known as Very Rapid. This transient signal is believed to represent an intermediate in...

The nature of the sulphur atom liberated from xanthine oxidase by cyanide. Evidence from e.p.r. spectroscopy after 35S substitution.

Malthouse, J P, Bray, R C

Active xanthine oxidase was labelled specifically with 33S in the cyanide-labile site of the molybdenum centre. The Very Rapid molybdenum (V) e.p.r. signal, generated from this, shows strong coupling...

The nature of the phosphate inhibitor complex of sulphite oxidase from electron-paramagnetic-resonance studies using oxygen-17.

Gutteridge, S, Lamy, M T, Bray, R C

Studies of the effect of substitution with 17O on the e.p.r. spectra at 9 and 35 GHz of Mo(V) in the phosphate complex of sulphite oxidase are reported. Substitution of 17O-enriched water for normal...

X-ray absorption spectroscopy of xanthine oxidase. The molybdenum centres of the functional and the desulpho forms.

Bordas, J, Bray, R C, Garner, C D, Gutteridge, S, Hasnain, S S

X-ray absorption spectra have been recorded for the molybdenum K-edge region of xanthine oxidase. Both the absorption edge and the extended fine structure (e.x.a.f.s.) regions were investigated....

Kinetic and e.p.r. studies on the inhibition of xanthine oxidase by alloxanthine (1 H-pyrazolo [3, 4-d] pyrimidine-4,6-diol).

Williams, J W, Bray, R C

The inhibition by alloxanthine of oxidation of xanthine by xanthine oxidase is characterized by a prolonged transient phase. Kinetic data accord with a mechanism that involves rapid formation of a...

Molybdenum(V) e.p.r. signals obtained from xanthine oxidase on reduction with aldehyde substrates and with 2-amino-4-hydroxy-6-formylpteridine.

Malthouse, J P, Williams, J W, Bray, R C

2-Amino-4-hydroxy-6-formylpteridine, a known 'slow' substrate and inhibitor of xanthine oxidase, is unusual in that it gives rise under suitable conditions to all types of molybdenum(V) e.p.r....

Coupling of [33S]sulphur to molybdenum(V) in different reduced forms of xanthine oxidase.

Malthouse, J P, George, G N, Lowe, D J, Bray, R C

Different reduced forms of xanthine oxidase, labelled specifically in the cyanide-labile site with 33S, were prepared and examined by electron paramagnetic resonance. Coupling of this isotope to...

Evidence from electron-paramagnetic-resonance spectroscopy for a complex of sulphite ions with the molybdenum centre of sulphite oxidase.

Bray, R C, Lamy, M T, Gutteridge, S, Wilkinson, T

Reduction of sulphite oxidase by sulphite at low pH values in Mes (4-morpholine-ethanesulphonic acid) buffer gives rise to a new molybdenum(V) electron-paramagnetic-resonance spectrum different from...

Oxidation-reduction potentials of molybdenum, flavin and iron-sulphur centres in milk xanthine oxidase.

Cammack, R, Barber, M J, Bray, R C

1. The mid-point reduction potentials of the various groups in xanthine oxidase from bovine milk were determined by potentiometric titration with dithionite in the presence of dye mediators, removing...

Oxidation--reduction potentials of turkey liver xanthine dehydrogenase and the origins of oxidase and dehydrogenase behaviour in molybdenum-containing hydroxylases.

Barber, M J, Bray, R C, Cammack, R, Coughlan, M P

Redox potentials for the various centres in the enzyme xanthine dehydrogenase (EC 1.2.1.37) from turkey liver determined by potentiometric titration in the presence of mediator dyes, with...

Studies by electron-paramagnetic-resonance spectroscopy on the mechanism of action of xanthine dehydrogenase from Veillonella alcalescens.

Dalton, H, Lowe, D J, Pawlik, T, Bray, R C

E.p.r- (electron-paramagnetic-resonance) spectroscopy was used to compare chemical environment and reactivity of molybdenum, flavin and iron-sulphur centres in the enzyme xanthine dehydrogenase from...

Studies by electron-paramagnetic-resonance spectroscopy and stopped-flow spectrophotometry on the mechanism of action of turkey liver xanthine dehydrogenase.

Barber, M J, Bray, R C, Lowe, D J, Coughlan, M P

Studies by e.p.r. (electron-paramagnetic-resonance) spectroscopy and by stopped-flow spectrophotometry on turkey liver xanthine dehydrogenase revealed strong similarities to as well as important...

A new non-functional form of milk xanthine oxidase containing stable quinquivalent molybdenum.

Lowe, D J, Barber, M J, Pawlik, R T, Bray, R C

A new non-functional modified form of milk xanthine oxidase is described. This contains molybdenum in a quinquivalent state, which is resistant to both oxidation and reduction. The new species is...

Electron-paramagnetic-resonance studies on the molybdenum of nitrate reductase from Escherichia coli K12.

Bray, R C, Vincent, S P, Lowe, D J, Clegg, R A, Garland, P B

Studies on the respiratory nitrate reductase (EC 1.7.99.4) from Escherichia coli K12 by electron-paramagnetic-resonance spectroscopy indicate that its molybdenum centre is comparable with that in...

Changes in apparent pH on freezing aqueous buffer solutions and their relevance to biochemical electron-paramagnetic-resonance spectroscopy.

Williams-Smith, D L, Bray, R C, Barber, M J, Tsopanakis, A D, Vincent, S P

Changes in apparent pH occurring during fast freezing of aqueous buffer solutions and cooling to -196 degrees C were studied by various semiquantitative methods, including simple visual measurements...

Magnetic coupling of the molybdenum and iron-sulphur centres in xanthine oxidase and xanthine dehydrogenases.

Lowe, D J, Bray, R C

Magnetic interaction between molybdenum and one of the iron-sulphur centres in milk xanthine oxidase [Lowe, Lynden-Bell & Bray (1972) Biochem. J. 130, 239-249] was studied further, with particular...

Electron-paramagnetic-resonance spectroscopy of complexes of xanthine oxidase with xanthine and uric acid.

Bray, R C, Barber, M J, Lowe, D J

Molybdenum(V) e.p.r. signals from reduced functional milk xanthine oxidase molecules (the Rapid signals), obtained in the presence of purine substrates and products, were further investigated [cf....

`Rapidly Appearing' molybdenum electron-paramagnetic-resonance signals from reduced xanthine oxidase

Bray, R. C., Vänngård, T.

Further electron-paramagnetic-resonance studies relating to the role of molybdenum in the enzymic mechanisms of xanthine oxidase were carried out. The classification of the various molybdenum signals...

Complex-formation between reduced xanthine oxidase and purine substrates demonstrated by electron paramagnetic resonance

Pick, Frances M., Bray, R. C.

The origin of the Rapid molybdenum electron-paramagnetic-resonance signals, which are obtained on reducing xanthine oxidase with purine or with xanthine, and whose parameters were measured by Bray &...

The composition of milk xanthine oxidase

Hart, L. I., McGartoll, Mary A., Chapman, Helen R., Bray, R. C.

The composition of milk xanthine oxidase has been reinvestigated. When the enzyme is prepared by methods that include a selective denaturation step in the presence of sodium salicylate the product is...

The molybdenum centre of native xanthine oxidase. Evidence for proton transfer from substrates to the centre and for existence of an anion-binding site.

Gutteridge, S, Tanner, S J, Bray, R C

The observation by Bray & Knowles [Proc. R. Soc. London Ser. A (1968) 302, 351--353] of direct transfer, during the catalytic reaction, of hydrogen atoms from substrate molecules to the enzyme...

pH-jump studies at subzero temperatures on an intermediate in the reaction of xanthine oxidase with xanthine.

Tsopanakis, A D, Tanner, S J, Bray, R C

Xanthine oxidase is stable and active in aqueous dimethyl sulphoxide solutions of up to at least 57% (w/w). Simple techniques are described for mixing the enzyme in this solvent at--82 degrees C,...

Comparison of the molybdenum centres of native and desulpho xanthine oxidase. The nature of the cyanide-labile sulphur atom and the nature of the proton-accepting group.

Gutteridge, S, Tanner, S J, Bray, R C

The non-functional form of xanthine oxidase known as the desulpho enzyme was compared with the functional enzyme in various ways, to obtain information on the structure of the molybdenum centre and...

The mechanism of action of xanthine oxidase. The relationship between the rapid and very rapid molybdenum electron-paramagnetic-resonance signals.

Bray, R C, Gutteridge, S, Stotter, D A, Tanner, S J

On the basis of the work of Gutteridge, Tanner & Bray [Biochem. J. (1978) 175, 887-897] and of other data in the literature, a mechanism for the reaction of xanthine oxidase with reducing substrates...

Electron-spin-resonance evidence for enzymic reduction of oxygen to a free radical, the superoxide ion

Knowles, P. F., Gibson, J. F., Pick, F. M., Bray, R. C.

1. An electron-spin-resonance signal with g∥2·08 and g⊥2·00 is observed by the rapid-freezing technique during the oxidation of substrates by molecular oxygen catalysed by xanthine oxidase at...

The chemistry of xanthine oxidase. Reaction with iodoacetamide

Bray, R. C., Watts, D. C.

1. The reaction of milk xanthine oxidase with iodoacetamide has been studied with the silver–silver iodide electrode. 2. The reaction proceeds considerably faster in the presence of xanthine than...

Enzymes in cancer: Asparaginase from chicken liver

Ohnuma, T., Bergel, F., Bray, R. C.

1. A procedure for partial purification of asparaginase from chicken liver is presented. 2. The bulk of the enzyme is located in the soluble fraction of chicken liver. 3. Molecular weights of...

Enzymes and cancer: Preparation and some properties of guanase from rabbit liver

Currie, R., Bergel, F., Bray, R. C.

1. Guanase has been purified 200-fold in 20% yield from the supernatant fraction of rabbit-liver homogenates, by using ammonium sulphate fractionation, calcium phosphate-gel adsorption and...

Spatial variation in sympathetic influences on the vasculature of the synovium and medial collateral ligament of the rabbit knee joint.

McDougall, J J, Ferrell, W R, Bray, R C

1. Laser Doppler perfusion imaging was used to assess the role of the sympathetic nervous system in the control of blood flow to the medial collateral ligament and capsule (synovium and overlying...

Normal and healing ligament vascularity: a quantitative histological assessment in the adult rabbit medial collateral ligament.

Bray, R C, Rangayyan, R M, Frank, C B

Normal and healing adult rabbit medial collateral ligaments (MCL) have been assessed for microvascular anatomy using a quantitative image analysis methodology. MCL preparation by ink-gelatin...

Fine vascular anatomy of adult rabbit knee ligaments.

Bray, R C, Fisher, A W, Frank, C B

The microvascular anatomy of discrete knee ligaments in adult rabbits is described. Epiligamentous plexuses give rise to a limited number of vessels which penetrate deeply into ligament substance....

Vascular alterations in the rabbit patellar tendon after surgical incision

DOSCHAK, M. R., MATYAS, J. R., HART, D. A., BRAY, R. C.

Open incision of the patellar tendon (PT) is thought to promote acute vascular responses which ultimately result in an enhanced degree of tendon repair. Such a clinical procedure is commonly applied...

MÖSSBAUER SPECTROSCOPY OF THE IRON-SULFUR PROTEINS*

Johnson, C. E., Bray, R. C., Cammack, R., Hall, D. O.

The Mössbauer spectra of 57Fe in two plant ferredoxins (from spinach and Euglena) and in xanthine oxidase have been measured at a series of temperatures and magnetic fields, and are found to be...

Information from e.p.r. spectroscopy on the iron-sulphur centres of the iron-molybdenum protein (aldehyde oxidoreductase) of Desulfovibrio gigas.

Bray, R C, Turner, N A, Le Gall, J, Barata, B A, Moura, J J

E.p.r. spectra of reduced iron-sulphur centres of the aldehyde oxidoreductase (iron-molybdenum protein) of Desulfovibrio gigas were recorded at X-band and Q-band frequencies and simulated. Results...

Use of rosy mutant strains of Drosophila melanogaster to probe the structure and function of xanthine dehydrogenase.

Hughes, R K, Doyle, W A, Chovnick, A, Whittle, J R, Burke, J F, Bray, R C

The usefulness in structure/function studies of molybdenum-containing hydroxylases in work with rosy mutant strains of Drosophila melanogaster has been investigated. At least 23 such strains are...

Isolation, in the intact state, of the pterin molybdenum cofactor from xanthine oxidase.

Deistung, J, Bray, R C

A procedure is described for isolation of the pterin molybdenum cofactor, in the active molybdenum-containing state, starting from purified milk xanthine oxidase. The method depends on the use of...

The isolation of demolybdo xanthine oxidase from bovine milk.

Ventom, A M, Deistung, J, Bray, R C

It was deduced many years ago from indirect evidence that demolybdo xanthine oxidase is present in normal bovine milk. This has now been confirmed by isolation of this enzyme form by a method based...

X-ray-absorption and electron-paramagnetic-resonance spectroscopic studies of the environment of molybdenum in high-pH and low-pH forms of Escherichia coli nitrate reductase.

George, G N, Turner, N A, Bray, R C, Morpeth, F F, Boxer, D H, Cramer, S P

Previous e.p.r. work [George, Bray, Morpeth & Boxer (1985) Biochem. J. 227, 925-931] has provided evidence for a pH- and anion-dependent transition in the structure of the Mo(V) centre of Escherichia...

Information from e.x.a.f.s. spectroscopy on the structures of different forms of molybdenum in xanthine oxidase and the catalytic mechanism of the enzyme.

Turner, N A, Bray, R C, Diakun, G P

X-ray spectroscopy was used to provide further information on the structure of the molybdenum centre of xanthine oxidase. Earlier work was confirmed and two states of the enzyme, not reported on by...

Studies by electron-paramagnetic-resonance spectroscopy of the environment of the metal in the molybdenum cofactor of molybdenum-containing enzymes.

Hawkes, T R, Bray, R C

The molybdenum cofactor prepared by denaturing xanthine oxidase by heat treatment or other methods was partially purified by anaerobic gel filtration in the presence of sodium dithionite, with little...

Electron-paramagnetic-resonance spectroscopy studies on the dissimilatory nitrate reductase from Pseudomonas aeruginosa.

Godfrey, C, Greenwood, C, Thomson, A J, Bray, R C, George, G N

Preparations of nitrate reductase in the resting state from Pseudomonas aeruginosa exhibit an Mo(V) e.p.r. signal. Progressive reduction of the enzyme results at first in the intensification and then...

Complexes with halide and other anions of the molybdenum centre of nitrate reductase from Escherichia coli.

George, G N, Bray, R C, Morpeth, F F, Boxer, D H

The interconversion of nitrate reductase from Escherichia coli between low-pH and high-pH Mo(V) e.p.r. signal-giving species was re-investigated [cf. Vincent & Bray (1978) Biochem. J. 171, 639-647]....

Comparison of the processes involved in reduction by the substrate for two homologous flavocytochromes b2 from different species of yeast.

Capeillère-Blandin, C, Barber, M J, Bray, R C

A detailed study of the electron exchanges involved between FMN and haem b2 groups within flavocytochrome b2 of yeast Hansenula anomala (H-enzyme) was performed. The results were compared with those...

The molybdenum iron-sulphur protein from Desulfovibrio gigas as a form of aldehyde oxidase.

Turner, N, Barata, B, Bray, R C, Deistung, J, Le Gall, J, Moura, J J

The molybdenum iron-sulphur protein originally isolated from Desulfovibrio gigas by Moura, Xavier, Bruschi, Le Gall, Hall & Cammack [(1976) Biochem. Biophys. Res. Commun. 72, 782-789] has been...

Investigation by electron paramagnetic resonance spectroscopy of the molybdenum centre of respiratory nitrate reductase from Paracoccus denitrificans.

Turner, N, Ballard, A L, Bray, R C, Ferguson, S

The molybdenum centre of respiratory nitrate reductase from Paracoccus denitrificans has been investigated by e.p.r. spectroscopy of Mo(V). In common with the centres of the analogous enzymes from...

Studies by electron-paramagnetic-resonance spectroscopy of the molybdenum centre of spinach (Spinacia oleracea) nitrate reductase.

Gutteridge, S, Bray, R C, Notton, B A, Fido, R J, Hewitt, E J

The molybdenum centre of spinach (Spinacia oleracea) nitrate reductase has been investigated by e.p.r. spectroscopy of molybdenum(V) in reduced forms of the enzyme. The resting enzyme gives no...

The effect of pH on the exchangeability with deuterium of protons coupled to molybdenum(V) in the active and the desulpho forms of xanthine oxidase.

Malthouse, J P, Bray, R C

The effect of pH variation on the exchangeability with deuterium of protons strongly coupled to Mo(V) in the active and desulpho forms of xanthine oxidase was studied by e.p.r. and rapid freezing, in...

Detection by low-temperature magnetic circular-dichroism spectroscopy of optical absorption bands due to molybdenum (V) in the form of xanthine oxidase giving the Desulpho Inhibited e.p.r. signal.

Peterson, J, Godfrey, C, Thomson, A J, George, G N, Bray, R C

The magnetic circular-dichroism (m.c.d.) spectra in the temperature range 1.5-100 K and the electronic absorption spectra at 4.2 and 295 K were measured for a number of desulpho xanthine oxidase...

The structure of the inhibitory complex of alloxanthine (1H-pyrazolo[3,4-d]pyrimidine-4,6-diol) with the molybdenum centre of xanthine oxidase from electron-paramagnetic-resonance spectroscopy.

Hawkes, T R, George, G N, Bray, R C

Studies were carried out on the inhibitory complex of alloxanthine (1H-pyrazolo[3,4-d]pyrimidine-4,5-diol) with xanthine oxidase, in extension of the work of Williams & Bray [Biochem. J. (1981) 195,...

Quantitative transfer of the molybdenum cofactor from xanthine oxidase and from sulphite oxidase to the deficient enzyme of the nit-1 mutant of Neurospora crassa to yield active nitrate reductase.

Hawkes, T R, Bray, R C

An assay method is described for measurement of absolute concentrations of the molybdenum cofactor, based on complementation of the defective nitrate reductase ('apo nitrate reductase') in extracts...

Formamide as a substrate of xanthine oxidase.

Morpeth, F F, George, G N, Bray, R C

Formamide is a substrate of xanthine oxidase. At pH 8.2 and 1.14 mM-O2, Vmax.(app.) is 3.1 s-1 and Km (app.) is 0.7 M. Mo(V) e.p.r. signals obtained by treating the enzyme with formamide were...

Equilibria amongst different molybdenum (V)-containing species from sulphite oxidase. Evidence for a halide ligand of molybdenum in the low-pH species.

Bray, R C, Gutteridge, S, Lamy, M T, Wilkinson, T

The interaction of chloride, fluoride and phosphate ions with the molybdenum centre of sulphite oxidase in the pH range 6.2 to 9.6 has been studied by e.p.r. of Mo(V) in the enzyme reduced by...

Studies by e.p.r. spectroscopy of carbon monoxide oxidases from Pseudomonas carboxydovorans and Pseudomonas carboxydohydrogena.

Bray, R C, George, G N, Lange, R, Meyer, O

E.p.r. spectra were obtained at 8-120 K for carbon monoxide oxidases isolated from the carboxydotrophic bacteria Pseudomonas carboxydovorans and Pseudomonas carboxydohydrogena. Spectra from the two...

Studies by electron-paramagnetic-resonance spectroscopy of the molybdenum centre of aldehyde oxidase.

Bray, R C, George, G N, Gutteridge, S, Norlander, L, Stell, J G, Stubley, C

Molybdenum(V) e.p.r. spectra from reduced forms of aldehyde oxidase were obtained and compared with those from xanthine oxidase. Inhibited and Desulpho Inhibited signals from aldehyde oxidase were...

Spatial variation in sympathetic influences on the vasculature of the synovium and medial collateral ligament of the rabbit knee joint.

McDougall, J J, Ferrell, W R, Bray, R C

1. Laser Doppler perfusion imaging was used to assess the role of the sympathetic nervous system in the control of blood flow to the medial collateral ligament and capsule (synovium and overlying...

Purification and properties of nitrogenase in ethylene glycol at sub-zero temperatures.

Tsopanakis, A D, Bray, R C, Smith, B E

Both the protein components Kp1 and Kp2 of nitrogenase from Klebsiella pneumoniae were found to be stable in aq. 50% (v/v) ethylene glycol at +30 degrees C or below. At -20 degrees C in this medium...

Rapid type 2 molybdenum(V) electron-paramagnetic resonance signals from xanthine oxidase and the structure of the active centre of the enzyme.

Malthouse, J P, Gutteridge, S, Bray, R C

Rapid type 2 molybdenum(V) e.p.r. signals from reduced functional xanthine oxidase have been further investigated. These signals, which show strong coupling of two protons to molybdenum, have been...

Oxygen-17 splitting of the very rapid molybdenum(V) e.p.r. signal from xanthine oxidase. Rate of exchange with water of the coupled oxygen atom.

Gutteridge, S, Bray, R C

Studies have been carried out of effects of 17O substitution on a Mo(V) e.p.r. signal from xanthine oxidase, known as Very Rapid. This transient signal is believed to represent an intermediate in...

The nature of the sulphur atom liberated from xanthine oxidase by cyanide. Evidence from e.p.r. spectroscopy after 35S substitution.

Malthouse, J P, Bray, R C

Active xanthine oxidase was labelled specifically with 33S in the cyanide-labile site of the molybdenum centre. The Very Rapid molybdenum (V) e.p.r. signal, generated from this, shows strong coupling...

The nature of the phosphate inhibitor complex of sulphite oxidase from electron-paramagnetic-resonance studies using oxygen-17.

Gutteridge, S, Lamy, M T, Bray, R C

Studies of the effect of substitution with 17O on the e.p.r. spectra at 9 and 35 GHz of Mo(V) in the phosphate complex of sulphite oxidase are reported. Substitution of 17O-enriched water for normal...

X-ray absorption spectroscopy of xanthine oxidase. The molybdenum centres of the functional and the desulpho forms.

Bordas, J, Bray, R C, Garner, C D, Gutteridge, S, Hasnain, S S

X-ray absorption spectra have been recorded for the molybdenum K-edge region of xanthine oxidase. Both the absorption edge and the extended fine structure (e.x.a.f.s.) regions were investigated....

Kinetic and e.p.r. studies on the inhibition of xanthine oxidase by alloxanthine (1 H-pyrazolo [3, 4-d] pyrimidine-4,6-diol).

Williams, J W, Bray, R C

The inhibition by alloxanthine of oxidation of xanthine by xanthine oxidase is characterized by a prolonged transient phase. Kinetic data accord with a mechanism that involves rapid formation of a...

Molybdenum(V) e.p.r. signals obtained from xanthine oxidase on reduction with aldehyde substrates and with 2-amino-4-hydroxy-6-formylpteridine.

Malthouse, J P, Williams, J W, Bray, R C

2-Amino-4-hydroxy-6-formylpteridine, a known 'slow' substrate and inhibitor of xanthine oxidase, is unusual in that it gives rise under suitable conditions to all types of molybdenum(V) e.p.r....

Coupling of [33S]sulphur to molybdenum(V) in different reduced forms of xanthine oxidase.

Malthouse, J P, George, G N, Lowe, D J, Bray, R C

Different reduced forms of xanthine oxidase, labelled specifically in the cyanide-labile site with 33S, were prepared and examined by electron paramagnetic resonance. Coupling of this isotope to...

Evidence from electron-paramagnetic-resonance spectroscopy for a complex of sulphite ions with the molybdenum centre of sulphite oxidase.

Bray, R C, Lamy, M T, Gutteridge, S, Wilkinson, T

Reduction of sulphite oxidase by sulphite at low pH values in Mes (4-morpholine-ethanesulphonic acid) buffer gives rise to a new molybdenum(V) electron-paramagnetic-resonance spectrum different from...

Oxidation-reduction potentials of molybdenum, flavin and iron-sulphur centres in milk xanthine oxidase.

Cammack, R, Barber, M J, Bray, R C

1. The mid-point reduction potentials of the various groups in xanthine oxidase from bovine milk were determined by potentiometric titration with dithionite in the presence of dye mediators, removing...

Oxidation--reduction potentials of turkey liver xanthine dehydrogenase and the origins of oxidase and dehydrogenase behaviour in molybdenum-containing hydroxylases.

Barber, M J, Bray, R C, Cammack, R, Coughlan, M P

Redox potentials for the various centres in the enzyme xanthine dehydrogenase (EC 1.2.1.37) from turkey liver determined by potentiometric titration in the presence of mediator dyes, with...

Normal and healing ligament vascularity: a quantitative histological assessment in the adult rabbit medial collateral ligament.

Bray, R C, Rangayyan, R M, Frank, C B

Normal and healing adult rabbit medial collateral ligaments (MCL) have been assessed for microvascular anatomy using a quantitative image analysis methodology. MCL preparation by ink-gelatin...

Studies by electron-paramagnetic-resonance spectroscopy on the mechanism of action of xanthine dehydrogenase from Veillonella alcalescens.

Dalton, H, Lowe, D J, Pawlik, T, Bray, R C

E.p.r- (electron-paramagnetic-resonance) spectroscopy was used to compare chemical environment and reactivity of molybdenum, flavin and iron-sulphur centres in the enzyme xanthine dehydrogenase from...

Studies by electron-paramagnetic-resonance spectroscopy and stopped-flow spectrophotometry on the mechanism of action of turkey liver xanthine dehydrogenase.

Barber, M J, Bray, R C, Lowe, D J, Coughlan, M P

Studies by e.p.r. (electron-paramagnetic-resonance) spectroscopy and by stopped-flow spectrophotometry on turkey liver xanthine dehydrogenase revealed strong similarities to as well as important...

A new non-functional form of milk xanthine oxidase containing stable quinquivalent molybdenum.

Lowe, D J, Barber, M J, Pawlik, R T, Bray, R C

A new non-functional modified form of milk xanthine oxidase is described. This contains molybdenum in a quinquivalent state, which is resistant to both oxidation and reduction. The new species is...

Electron-paramagnetic-resonance studies on the molybdenum of nitrate reductase from Escherichia coli K12.

Bray, R C, Vincent, S P, Lowe, D J, Clegg, R A, Garland, P B

Studies on the respiratory nitrate reductase (EC 1.7.99.4) from Escherichia coli K12 by electron-paramagnetic-resonance spectroscopy indicate that its molybdenum centre is comparable with that in...

Changes in apparent pH on freezing aqueous buffer solutions and their relevance to biochemical electron-paramagnetic-resonance spectroscopy.

Williams-Smith, D L, Bray, R C, Barber, M J, Tsopanakis, A D, Vincent, S P

Changes in apparent pH occurring during fast freezing of aqueous buffer solutions and cooling to -196 degrees C were studied by various semiquantitative methods, including simple visual measurements...

Magnetic coupling of the molybdenum and iron-sulphur centres in xanthine oxidase and xanthine dehydrogenases.

Lowe, D J, Bray, R C

Magnetic interaction between molybdenum and one of the iron-sulphur centres in milk xanthine oxidase [Lowe, Lynden-Bell & Bray (1972) Biochem. J. 130, 239-249] was studied further, with particular...

Electron-paramagnetic-resonance spectroscopy of complexes of xanthine oxidase with xanthine and uric acid.

Bray, R C, Barber, M J, Lowe, D J

Molybdenum(V) e.p.r. signals from reduced functional milk xanthine oxidase molecules (the Rapid signals), obtained in the presence of purine substrates and products, were further investigated [cf....

`Rapidly Appearing' molybdenum electron-paramagnetic-resonance signals from reduced xanthine oxidase

Bray, R. C., Vänngård, T.

Further electron-paramagnetic-resonance studies relating to the role of molybdenum in the enzymic mechanisms of xanthine oxidase were carried out. The classification of the various molybdenum signals...

Complex-formation between reduced xanthine oxidase and purine substrates demonstrated by electron paramagnetic resonance

Pick, Frances M., Bray, R. C.

The origin of the Rapid molybdenum electron-paramagnetic-resonance signals, which are obtained on reducing xanthine oxidase with purine or with xanthine, and whose parameters were measured by Bray &...

The composition of milk xanthine oxidase

Hart, L. I., McGartoll, Mary A., Chapman, Helen R., Bray, R. C.

The composition of milk xanthine oxidase has been reinvestigated. When the enzyme is prepared by methods that include a selective denaturation step in the presence of sodium salicylate the product is...

The molybdenum centre of native xanthine oxidase. Evidence for proton transfer from substrates to the centre and for existence of an anion-binding site.

Gutteridge, S, Tanner, S J, Bray, R C

The observation by Bray & Knowles [Proc. R. Soc. London Ser. A (1968) 302, 351--353] of direct transfer, during the catalytic reaction, of hydrogen atoms from substrate molecules to the enzyme...

pH-jump studies at subzero temperatures on an intermediate in the reaction of xanthine oxidase with xanthine.

Tsopanakis, A D, Tanner, S J, Bray, R C

Xanthine oxidase is stable and active in aqueous dimethyl sulphoxide solutions of up to at least 57% (w/w). Simple techniques are described for mixing the enzyme in this solvent at--82 degrees C,...

Comparison of the molybdenum centres of native and desulpho xanthine oxidase. The nature of the cyanide-labile sulphur atom and the nature of the proton-accepting group.

Gutteridge, S, Tanner, S J, Bray, R C

The non-functional form of xanthine oxidase known as the desulpho enzyme was compared with the functional enzyme in various ways, to obtain information on the structure of the molybdenum centre and...

The mechanism of action of xanthine oxidase. The relationship between the rapid and very rapid molybdenum electron-paramagnetic-resonance signals.

Bray, R C, Gutteridge, S, Stotter, D A, Tanner, S J

On the basis of the work of Gutteridge, Tanner & Bray [Biochem. J. (1978) 175, 887-897] and of other data in the literature, a mechanism for the reaction of xanthine oxidase with reducing substrates...

Electron-spin-resonance evidence for enzymic reduction of oxygen to a free radical, the superoxide ion

Knowles, P. F., Gibson, J. F., Pick, F. M., Bray, R. C.

1. An electron-spin-resonance signal with g∥2·08 and g⊥2·00 is observed by the rapid-freezing technique during the oxidation of substrates by molecular oxygen catalysed by xanthine oxidase at...

Fine vascular anatomy of adult rabbit knee ligaments.

Bray, R C, Fisher, A W, Frank, C B

The microvascular anatomy of discrete knee ligaments in adult rabbits is described. Epiligamentous plexuses give rise to a limited number of vessels which penetrate deeply into ligament substance....

The chemistry of xanthine oxidase. Reaction with iodoacetamide

Bray, R. C., Watts, D. C.

1. The reaction of milk xanthine oxidase with iodoacetamide has been studied with the silver–silver iodide electrode. 2. The reaction proceeds considerably faster in the presence of xanthine than...

Enzymes in cancer: Asparaginase from chicken liver

Ohnuma, T., Bergel, F., Bray, R. C.

1. A procedure for partial purification of asparaginase from chicken liver is presented. 2. The bulk of the enzyme is located in the soluble fraction of chicken liver. 3. Molecular weights of...

Enzymes and cancer: Preparation and some properties of guanase from rabbit liver

Currie, R., Bergel, F., Bray, R. C.

1. Guanase has been purified 200-fold in 20% yield from the supernatant fraction of rabbit-liver homogenates, by using ammonium sulphate fractionation, calcium phosphate-gel adsorption and...

Vascular alterations in the rabbit patellar tendon after surgical incision

DOSCHAK, M. R., MATYAS, J. R., HART, D. A., BRAY, R. C.

Open incision of the patellar tendon (PT) is thought to promote acute vascular responses which ultimately result in an enhanced degree of tendon repair. Such a clinical procedure is commonly applied...

Spatial heterogeneity of the effects of calcitonin gene-related peptide (CGRP) on the microvasculature of ligaments in the rabbit knee joint

Ferrell, W R, McDougall, J J, Bray, R C

Experiments were performed in anaesthetized rabbits to examine the effects of calcitonin gene-related peptide (CGRP) and the CGRP antagonist CGRP8–37 on blood flow to the medial collateral ligament...