scholarly journals SULFHYDRYL GROUPS OF EGG ALBUMIN IN DIFFERENT DENATURING AGENTS

1941 ◽  
Vol 24 (6) ◽  
pp. 709-723 ◽  
Author(s):  
A. E. Mirsky
Keyword(s):  
Isoelectric Point ◽  
Guanidine Hydrochloride ◽  
Sulfhydryl Groups ◽  
Color Reaction ◽  
Neutral Medium ◽  
Egg Albumin ◽  
Sh Groups ◽  
Cysteine Content

1. The reaction between ferricyanide and egg albumin in solutions of urea, guanidine hydrochloride, and Duponol has been investigated. 2. In neutral medium ferricyanide oxidizes all the SH groups of egg albumin that give a color reaction with nitroprusside. In neutral medium ferricyanide appears to react only with the SH groups of egg albumin. The quantity of ferrocyanide formed can accordingly be considered the equivalent of the number of SH groups in egg albumin detectable with nitroprusside. 3. In solutions of urea, guanidine hydrochloride, and Duponol sufficiently concentrated so that all the egg albumin present is denatured, the same number of SH groups are found—equivalent to a cysteine content of 0.96 per cent. 4. In denaturation of egg albumin loss of solubility (solubility not in presence of the denaturing agent, but solubility examined in water at the isoelectric point) and appearance of reactive SH groups are integral parts of the same process. As denaturation proceeds in urea, SH groups are liberated only in the egg albumin with altered solubility and in this albumin the maximum number of SH groups is liberated. In a molecule of egg albumin either all of its SH groups that give a test with nitroprusside are liberated or none of them are.

scholarly journals THE SULFHYDRYL GROUPS OF EGG ALBUMIN

1941 ◽  
Vol 24 (4) ◽  
pp. 399-421 ◽  
Author(s):  
M. L. Anson
Keyword(s):  
Guanidine Hydrochloride ◽  
Sulfhydryl Groups ◽  
Urea Solution ◽  
Ferricyanide Reduction ◽  
Native Form ◽  
Egg Albumin ◽  
Sh Groups ◽  
Reduction Test ◽  
Hydrochloride Solution

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. Both the nitroprusside test and the ferricyanide reduction test are used to show that the SH groups have been abolished. 2. 1 cc. of 0.001 M ferrocyanide is formed when ferricyanide is added to 10 mg. of denatured egg albumin in neutral guanidine hydrochloride or urea solution. The amount of ferricyanide reduced to ferrocyanide by the SH groups of the denatured egg albumin is, within wide limits, independent of the ferricyanide concentration. 3. Ferricyanide and p-chloromercuribenzoate react more rapidly than tetrathionate with the SH groups of denatured egg albumin in both guanidine hydrochloride solution and in Duponol PC solution. 4. Cyanide inhibits the oxidation of the SH groups of denatured egg albumin by ferricyanide. 5. Some samples of guanidine hydrochloride contain impurities which bring about the abolition of SH groups of denatured egg albumin and so interfere with the SH titration and the nitroprusside test. This interference can be diminished by using especially purified guanidine hydrochloride, adding the titrating agent before the protein has been allowed to stand in guanidine hydrochloride solution, and carrying out the nitroprusside test in the presence of a small amount of cyanide. 6. The SH groups of egg albumin can be abolished by reaction of the native form of the protein with iodine. It is possible to oxidize all the SH groups with iodine without oxidizing many of the SH groups beyond the S-S stage and without converting many tyrosine groups into di-iodotyrosine groups. 7. p-chloromercuribenzoate combines with native egg albumin either not at all or much more loosely than it combines with the SH groups of denatured egg albumin or of cysteine. 8. The compound of mercuribenzoate and SH, like the compound of aldehyde and SH and like the SH in native egg albumin, does not give a nitroprusside test or reduce ferricyanide but does reduce iodine.

scholarly journals SULFHYDRYL GROUPS IN FILMS OF EGG ALBUMIN

1941 ◽  
Vol 24 (6) ◽  
pp. 725-733 ◽  
Author(s):  
A. E. Mirsky
Keyword(s):  
Film Formation ◽  
Surface Film ◽  
Guanidine Hydrochloride ◽  
Sulfhydryl Groups ◽  
Surface Films ◽  
Fundamental Change ◽  
Egg Albumin ◽  
Sh Groups ◽  
Denatured Proteins ◽  
Albumin Molecule

1. The same number of SH groups reduces ferricyanide in surface films of egg albumin as in albumin denatured by urea, guanidine hydrochloride, Duponol, or heat, provided the ferricyanide reacts with films while they still are at the surface and with the denatured proteins while the denaturing agent (urea, heat, etc.) is present. 2. The SH groups of a suspension of egg albumin made by clumping together many surface films react with ferricyanide in the same sluggish and incomplete manner as do the groups in egg albumin denatured by concentrated urea when the urea is diluted or in albumin denatured by heat when the solution is allowed to cool off. 3. The known change in configuration of the egg albumin molecule when it forms part of a surface film explains why SH groups in the film react with ferricyanide whereas those in native egg albumin do not. In the native egg albumin molecule groups in the interior are inaccessible to certain reagents. A film is so thin that there are no inaccessible groups. 4. Because of the marked resemblance in the properties of egg albumin in surface films and of egg albumin after denaturation by the recognized denaturing agents, it may be supposed that the same fundamental change takes place in denaturation as in film formation—indeed, that film formation is one of the numerous examples of denaturation. This would mean that in general the SH groups of denatured egg albumin reduce ferricyanide and react with certain other reagents because they are no longer inaccessible to these reagents.

scholarly journals SOME FACTORS WHICH INFLUENCE THE OXIDATION OF SULFHYDRYL GROUPS

1942 ◽  
Vol 25 (3) ◽  
pp. 355-367 ◽  
Author(s):  
M. L. Anson
Keyword(s):  
Uric Acid ◽  
Acid Solution ◽  
Copper Sulfate ◽  
Guanidine Hydrochloride ◽  
Sulfate Solution ◽  
Alkyl Sulfate ◽  
Neutral Solution ◽  
Egg Albumin ◽  
Sh Groups ◽  
Acid Reagent

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 the presence but not in the absence of added copper sulfate. 3. In neutral solution, the uric acid reagent oxidizes the SH groups of denatured egg albumin in the presence of urea but not in the presence of alkyl sulfate or in the absence of denaturing agents. 4. Ferricyanide oxidizes the SH groups of neutral denatured egg albumin even in the presence of alkyl sulfate or, if precautions are taken to avoid aggregation, in the absence of denaturing agents. 5. In acid solution, ferricyanide does not oxidize the SH groups of denatured egg albumin completely. The oxidation is more complete, however, in the presence of urea than in the presence of alkyl sulfate, and more complete in the presence of guanidine hydrochloride than in the presence of urea. 6. The uric acid reagent which does not oxidize the SH groups of neutral denatured but unhydrolyzed egg albumin in the absence of denaturing agents does, under the same conditions, oxidize the SH groups of egg albumin partially hydrolyzed by pepsin. 7. At pH 4.8 in alkyl sulfate solution ferricyanide oxidizes the SH groups of digested egg albumin more completely than the SH groups of denatured but undigested egg albumin.

scholarly journals SULFHYDRYL AND DISULFIDE GROUPS OF PROTEINS

1935 ◽  
Vol 18 (3) ◽  
pp. 307-323 ◽  
Author(s):  
A. E. Mirsky ◽  
M. L. Anson
Keyword(s):  
Protein S ◽  
Sh Groups ◽  
Cystine Content ◽  
Cysteine Content

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 content of proteins by the Folin-Marenzi method to take into account any cysteine that may be present. 3. A method for estimating the cysteine content of proteins has been described. 4. With these methods, estimations have been made of the S-S and SH groups and of the cystine and cysteine contents of a number of proteins. 5. In a denatured, but unhydrolyzed protein, the number of S-S and SH groups is equivalent to the quantity of cystine and cysteine found in the protein after hydrolysis.

The cysteine content of caseion micelles

1964 ◽  
Vol 31 (3) ◽  
pp. 285-290 ◽  
Author(s):  
R. D. Hill
Keyword(s):  
Enzymic Digestion ◽  
Sh Groups ◽  
Micellar Casein ◽  
Alkaline Conditions ◽  
Cysteine Content

SummaryFollowing enzymic digestion with pronase, masked SH groups in micellar casein became available for titration in disaggregating media with mercurial reagents. The content of cystine and cysteine was also estimated after reduction with (a) sulphite, and (b) borohydride, and also by reaction in alkaline conditions with Cd(OH)2. The results show that the micelles contain mainly cysteine, and that it is likely that cystine is not present.

New approaches to the role of sulfhydryl groups in silver stainability of protein in grasshopper chromosomes

Genome ◽  
1988 ◽  
Vol 30 (2) ◽  
pp. 133-137 ◽  
Author(s):  
J. de la Torre ◽  
J. L. Bella ◽  
C. López-Fernandez ◽  
J. Gosálvez
Keyword(s):  
Silver Staining ◽  
Chemical Nature ◽  
Germ Line ◽  
Staining Technique ◽  
Sulfhydryl Groups ◽  
Sh Groups ◽  
New Approaches ◽  
Silver Staining Technique ◽  
Reduced State

Silver staining in somatic and germ line cells of the grasshopper Arcyptera fusca has been analyzed after a standard silver staining technique was used with pretreatments that included dithiothreitol and β-mercaptoethanol as reagents to maintain —SH groups in the reduced state. The results show that in some tissues, these pretreatments improve not only the silver staining of nucleolar masses but also the recognition of other silver spots associated with the chromatin. These observations are similar to those previously described for the effect of double-strength standard saline citrate on silver staining. The possible chemical nature of the protein groups responsible for the differential silver stainability and the role of saline citrate in the modification of argyrophylic proteins suggested previously are briefly discussed.Key words: Orthoptera, silver staining, sulfhydryl groups.

scholarly journals THE ADSORPTION OF EGG ALBUMIN ON COLLODION MEMBRANES

1936 ◽  
Vol 19 (6) ◽  
pp. 907-916 ◽  
Author(s):  
Philip Dow
Keyword(s):  
Aqueous Solution ◽  
Experimental Study ◽  
Isoelectric Point ◽  
Protein Concentration ◽  
Adsorption Behavior ◽  
Adsorption From Solutions ◽  
Egg Albumin ◽  
Alkaline Side

An experimental study has been made of the adsorption of purified egg albumin, from aqueous solution, on collodion membranes. At protein concentrations of 4 to 7 per cent apparent saturation values were obtained which resembled closely the results obtained with gelatin, showing a maximum at pH 5.0 and lower values on either side of this region. Over large ranges of protein concentration, however, the curves for the adsorption from solutions removed in either direction from the isoelectric point exhibited a different shape from the hyperbola obtained in the neighborhood of pH 5.0. The addition of NaCl to solutions on the acid side tended to obliterate the effect of the pH difference; on the alkaline side it greatly increased the adsorption. The adsorption at 25° was about twice as great as that at 1°. The theory of the swelling of submicroscopic particles, advanced to account for the adsorption behavior of gelatin, is not sufficient to explain the results obtained with egg albumin. It is suggested that the effect is related to alterations in the forces causing the retention of the protein on the membranes.

FREE SULFHYDRYL GROUPS IN HAPTOGLOBIN

1967 ◽  
Vol 45 (4) ◽  
pp. 551-556 ◽  
Author(s):  
Brenda L. Tattrie ◽  
G. E. Connell
Keyword(s):  
Acid Hydrolysis ◽  
Guanidine Hydrochloride ◽  
Spectrophotometric Titration ◽  
Sulfhydryl Groups

Human haptoglobin of types 1-1 and 2-2 has been examined for its content of free sulfhydryl groups by two methods: (i) treatment of haptoglobin in the presence of 7.2 M guanidine hydrochloride with 14C-iodoacetate followed by acid hydrolysis and determination of 14C-carboxymethylcysteine content, and (ii) spectrophotometric titration of haptoglobin in the presence of 7.2 M guanidine hydrochloride with p-chloromercuribenzoate. By both methods, the content of free sulfhydryl was less than 1 equiv/105 g of protein.

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