ON SOME GENERAL PROPERTIES OF PROTEINS
1. The processes of denaturation and coagulation of hemoglobin are like those of other proteins. 2. When hemoglobin is denatured it is probably depolymerized into hemochromogen. 3. When other...
PROTEIN COAGULATION AND ITS REVERSAL : THE REVERSAL OF THE COAGULATION OF HEMOGLOBIN
1. The preparation from completely coagulated hemoglobin of crystalline soluble hemoglobin is described. 2. This soluble hemoglobin by all the tests tried has been indistinguishable from normal...
THE PREPARATION OF COMPLETELY COAGULATED HEMOGLOBIN
As a preliminary to the study of the reversal of the coagulation of hemoglobin several methods are described for the preparation of completely denatured and coagulated hemoglobin and the evidence is...
PROTEIN COAGULATION AND ITS REVERSAL : SERUM ALBUMIN
1. It is possible to prepare crystalline, soluble, heat-coagulable serum albumin from coagulated serum albumin. 2. In the cases so far studied, the more soluble a denatured protein, the more easily...
The coagulation of hemoglobin is probably reversible. Several methods are described for preparing soluble crystalline hemoglobin from hemoglobin denatured by HCl or trichloracetic acid. The yield is...
PROTEIN COAGULATION AND ITS REVERSAL : THE PREPARATION OF INSOLUBLE GLOBIN, SOLUBLE GLOBIN AND HEME
1. By a procedure involving the use of acid acetone hemoglobin may be rapidly separated into a precipitate of denatured globin and an acetone solution of heme. 2. By neutralization procedures the...
THE REACTIONS OF CYANIDE WITH GLOBIN HEMOCHROMOGEN
Cyanide can react with globin hemochromogen in two different ways. In the first reaction cyanide combines with globin hemochromogen without displacing or competing with globin. In the second reaction...
PROTEIN COAGULATION AND ITS REVERSAL : GLOBIN
1. The globin prepared from hemoglobin by the acid acetone method is denatured globin. 2. The denaturation and coagulation of globin by acid acetone are reversible. 3. Soluble globin can be obtained...
1. Methemoglobin prepared from coagulated hemoglobin by the reversal of coagulation has the same solubility within 2 per cent as normal methemoglobin. 2. Methemoglobin synthesized from hemin and the...
THE EFFECT OF DENATURATION ON THE VISCOSITY OF PROTEIN SYSTEMS
The viscosity of a protein solution is increased by the denaturation of the protein. This is true both when there is the formation of protein aggregates which occlude water and when there is no...
THE ESTIMATION OF TRYPSIN WITH HEMOGLOBIN
The formation from hemoglobin of split products not precipitable by trichloracetic acid is taken as a measure of tryptic activity. The split products are estimated colorimetrically. Many measurements...
THE ESTIMATION OF ACTIVE NATIVE TRYPSIN IN THE PRESENCE OF INACTIVE DENATURED TRYPSIN
Inactive denatured trypsin changes into active native trypsin in the protein solutions which have been used to estimate tryptic activity. If the digestion mixture, however, is alkaline enough and...
The denaturation of hemoglobin by salicylate in neutral solution is completely reversible. There is a mobile equilibrium between native and denatured hemoglobin in neutral salicylate solution. The...
MOLECULAR WEIGHT, MOLECULAR VOLUME, AND HYDRATION OF PROTEINS IN SOLUTION
Kunitz, M., Anson, M. L., Northrop, John H.
1. The gram molecular weight of a substance may be calculated from the osmotic pressure of its solution. 2. The radius of the hydrated molecule and, hence, the gram molecular volume of the hydrated...
THE EQUILIBRIUM BETWEEN ACTIVE NATIVE TRYPSIN AND INACTIVE DENATURED TRYPSIN
There is a mobile equilibrium between the native and denatured forms of trypsin which depends on the concentrations of acid, alkali, and alcohol and on the temperature. The heat of denaturation in...
SULFHYDRYL AND DISULFIDE GROUPS OF PROTEINS : I. METHODS OF ESTIMATION
1. Methods have been described for reducing protein S-S groups, for oxidizing protein SH groups, and for estimating protein S-S and SH groups. 2. It has been found necessary in estimating the cystine...
Hemoglobin and the proteins of the crystalline lens contain active SH groups while in the native state, the number of active groups increasing as the pH rises. All the SH groups of denatured globin...
1. In native egg albumin no SH groups are detectable, whereas in completely coagulated albumin as many groups are detectable as are found in the hydrolyzed protein. In egg albumin partially...
THE REDUCING GROUPS OF PROTEINS
1. Intact, unhydrolyzed proteins possess in addition to SH groups other reducing groups which can be oxidized by ferricyanide. 2. The activity of these reducing groups, like that of SH groups, is...
SOME FACTORS WHICH INFLUENCE THE OXIDATION OF SULFHYDRYL GROUPS
1. Cyanide inhibits the oxidation of the SH groups of cysteine and denatured egg albumin by the uric acid reagent. 2. At pH 4.8 cysteine is oxidized by the uric acid reagent and by ferricyanide in...
REACTION OF ENZYMES AND PROTEINS WITH MUSTARD GAS (BIS(β-CHLOROETHYL)SULFIDE)
Herriott, Roger M., Anson, M. L., Northrop, John H.
1. The rate of reaction of mustard gas (H) with thirteen proteins has been determined. The extreme variation in reaction rates is about 100:1. 2. No qualitative difference in the results was observed...
THE REACTIONS OF DENATURED EGG ALBUMIN WITH FERRICYANIDE
The following facts have been established experimentally. 1. In the presence of the synthetic detergent, Duponol PC, there is a definite reaction between dilute ferricyanide and denatured egg...
THE REACTIONS OF IODINE AND IODOACETAMIDE WITH NATIVE EGG ALBUMIN
The following experimental results have been obtained. 1. Native egg albumin treated with iodine and then denatured no longer gives a nitroprusside test or reduces dilute ferricyanide in neutral...
1. One mg. of the purified cathepsin whose preparation is described is as active as the extract of 1.3 gm. of spleen. An eightfold further purification is possible by procedures which are still being...
THE SULFHYDRYL GROUPS OF EGG ALBUMIN
1. 1 cc. of 0.001 M ferricyanide, tetrathionate, or p-chloromercuribenzoate is required to abolish the SH groups of 10 mg. of denatured egg albumin in guanidine hydrochloride or Duponol PC solution....
SOME EFFECTS OF IODINE AND OTHER REAGENTS ON THE STRUCTURE AND ACTIVITY OF TOBACCO MOSAIC VIRUS
1. Denatured tobacco mosaic virus has a number of SH groups corresponding to its total sulfur content of 0.2 per cent. The SH groups were estimated by titration with ferricyanide, tetrathionate, and...
1. Every hemochromogen consists of the iron pyrrol complex, reduced heme, combined with some nitrogenous substance. 2. In every hemochromogen there is the equilibrium: Hemochromogen ⇄ Reduced heme...
1. A method is described for estimating the heme in yeast and bees' muscles as pyridine hemochromogen. 2. The difficulties of the method are discussed. 3. The heme as given by the pyridine method is...
Northrop, John H., Anson, M. L.
A method is described for determining the diffusion coefficient of solutes by determining the rate of passage of the solute through a thin porous membrane between two solutions of different...
1. Cyanide hemochromogen probably contains one cyanide group per heme group. 2. The equilibrium between pyridine hemochromogen and its components, pyridine and reduced heme, is complicated to an...