scholarly journals STUDIES ON THE MECHANISM OF HYDROGEN TRANSPORT IN ANIMAL TISSUES

1943 ◽  
Vol 26 (4) ◽  
pp. 391-404 ◽  
Author(s):  
V. R. Potter ◽  
K. P. DuBois
Keyword(s):  
Succinic Dehydrogenase ◽  
Sulfhydryl Group ◽  
Carboxyl Groups ◽  
Common Denominator ◽  
Hydrogen Transport ◽  
Animal Tissues ◽  
Sulfhydryl Reagents ◽  
Sh Groups ◽  
Copper Zinc ◽  
Sulfhydryl Compounds

1. The mechanism of succinic dehydrogenase action was studied by means of inhibitors. 2. The enzyme is inhibited by a large number of diverse compounds whose only common denominator appears to be their ability to react with SH groups. These compounds include quinonoid structures, sulfhydryl reagents, sulfhydryl compounds, copper, zinc, selenite, and arsenite. 3. In contrast to the above inhibitors, the action of malonate does not appear to involve sulfhydryl groups and is explained on the basis of its affinity for the enzyme groups which react with the carboxyl groups of succinate. 4. The action of malonate and the sulfhydryl reactants is mutually exclusive, and this fact suggests the conclusion that the sulfhydryl group of the enzyme is located between the carboxyl affinity points. 5. On the basis of the deduced structure of the succinate-activating center of the enzyme, it is suggested that the enzyme may function by oscillating between the EnSH and EnS· forms, rather than by a thiol-disulfide equilibrium.

scholarly journals STUDIES ON THE MECHANISM OF HYDROGEN TRANSPORT IN ANIMAL TISSUES

1943 ◽  
Vol 26 (5) ◽  
pp. 443-455 ◽  
Author(s):  
V. R. Potter ◽  
H. G. Albaum
Keyword(s):  
Alkaline Phosphatase ◽  
Cytochrome C ◽  
Xanthine Oxidase ◽  
Cytochrome Oxidase ◽  
Adenosine Triphosphatase ◽  
Succinic Dehydrogenase ◽  
Hydrogen Transport ◽  
Animal Tissues ◽  
Cytochrome C Reductase ◽  
Enzyme Systems

1. The effect of ribonuclease on various enzyme systems was studied as one approach to the problem of whether or not these enzymes are contained in macromolecules of ribonucleoprotein nature in protoplasm. 2. Ribonuclease inhibited CoI-cytochrome c reductase, succinic dehydrogenase, and cytochrome oxidase, all of which require cytochrome c in order to function. Ribonuclease did not act on cytochrome c. 3. Ribonuclease did not inhibit urease, xanthine oxidase, catalase, alkaline phosphatase, or adenosine triphosphatase under the conditions employed. 4. It was suggested that ribonuclease acted sterically by preventing contact between cytochrome c and its activating centers. 5. It was suggested that the enzymes inhibited may be contained in a ribonucleoprotein of macromolecular dimensions but that the enzymes not inhibited are not necessarily excluded from such a complex by the data presented. 6. Further evidence against the Szent-Györgyi theory of hydrogen transport was presented and discussed.

scholarly journals STUDIES ON THE MECHANISM OF HYDROGEN TRANSPORT IN ANIMAL TISSUES

1942 ◽  
Vol 142 (2) ◽  
pp. 543-555 ◽  
Author(s):  
V.R. Potter ◽  
W.C. Schneider
Keyword(s):  
Hydrogen Transport ◽  
Animal Tissues

THE MECHANISM OF HYDROGEN TRANSPORT IN ANIMAL TISSUES

Medicine ◽  
1940 ◽  
Vol 19 (4) ◽  
pp. 441-474 ◽  
Author(s):  
VAN R. POTTER
Keyword(s):  
Hydrogen Transport ◽  
Animal Tissues

scholarly journals The Action of Two Sulfhydryl Compounds on Normal Human Red Cells

Blood ◽  
1965 ◽  
Vol 25 (4) ◽  
pp. 502-510 ◽  
Author(s):  
GIROLAMO SIRCHIA ◽  
SOLDANO FERRONE ◽  
FRANCESCO MERCURIALI
Keyword(s):  
Mechanism Of Action ◽  
Paroxysmal Nocturnal Hemoglobinuria ◽  
Red Cells ◽  
Experimental Conditions ◽  
Sh Groups ◽  
Normal Human ◽  
Sulfhydryl Compounds ◽  
Human Red Cells

Abstract Treatment of normal human red cells with AET and cysteine, under suitable experimental conditions, modifies them in such a way that their behavior in in vitro hemolysis tests becomes similar to that of the erythrocytes of paroxysmal nocturnal hemoglobinuria. It is felt that alteration of the red cells is due to the -SH groups possessed by both substances. A possible mechanism of action is hypothesized.

Investigations into the role of sulfhydryl groups in the mechanism of action of the nitrates

1982 ◽  
Vol 60 (10) ◽  
pp. 1261-1266 ◽  
Author(s):  
J. A. Moffat ◽  
P. W. Armstrong ◽  
G. S. Marks
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Mechanism Of Action ◽  
Active Site ◽  
Sulfhydryl Reagents ◽  
Response Curves ◽  
Sh Groups ◽  
Nitrobenzoic Acid ◽  
Sh Group

The mechanism by which nitroglycerin (GTN) initiates relaxation in vascular smooth muscle is not known. According to one hypothesis a specific nitrate receptor exists with a key sulfhydryl (SH) group in the active site. The current study was performed with sulfhydryl reagents in helical strips of the canine medial saphenous vein from 20 dogs to examine the role of the SH group in the action of GTN. The reagents used were 5,5′-dithiobis(2-nitrobenzoic acid) (DTNB) and p-chloromercuribenzoate (PCMB) which bind to and inactivate SH groups, and dithiothreitol (DTT), an SH reducing agent. It was anticipated that DTNB and PCMB would decrease the sensitivity to GTN while DTT might increase the sensitivity to GTN. Treatment of strips with PCMB and DTNB did not alter the dose–response curves for GTN. In contrast, following DTT treatment (1 × 10−4 M) the maximum response to GTN (10−5 M) was significantly reduced from 80.3% ± 4.0 (SD) in control strips to 46.9% ± 4.4 (SD) in the treated strips. These data suggest that relaxation induced by GTN in vascular smooth muscle occurs by a mechanism other than interaction with membrane SH groups.

The influence of haptoglobin on the reactivity of the –SH groups of hemoglobin

1969 ◽  
Vol 47 (12) ◽  
pp. 1205-1208 ◽  
Author(s):  
B. Malchy ◽  
G. H. Dixon
Keyword(s):  
Conformation Change ◽  
Sulfhydryl Reagents ◽  
Sh Groups ◽  
Rate Of Reaction

The rate of reaction of the β93 sulfhydryl of hemoglobin with iodoacetamide and 2,2′-, and 4,4′- dithiodipyridine is much slower when the hemoglobin is bound by haptoglobin than when it is free. However, these sulfhydryl reagents will react with the haemoglobin–haptoglobin complex, and the reaction of the complex with iodoacetamide is still at position β93. The results suggest that haptoglobin might induce a conformation change on oxyhemoglobin which is similar to that occurring upon deoxygenation.

Synthesis of pressinoic acid by enzymatically catalyzed formation of peptide bonds

1986 ◽  
Vol 51 (6) ◽  
pp. 1352-1360 ◽  
Author(s):  
Václav Čeřovský
Keyword(s):  
Methyl Esters ◽  
Sulfhydryl Group ◽  
Carboxyl Groups ◽  
Amino Groups ◽  
Peptide Bonds ◽  
Fragment Condensation

Three fully enzymatic syntheses of the 1-6 vasopressin hexapeptide were investigated using papain, α-chymotrypsin and thermolysin. Best results were obtained with thermolysin in the 2 + 4 fragment condensation. The α-chymotrypsin-catalyzed 3 + 3 condensation is less advantageous and the 4 + 2 condensation with papain gave only low yield. Using the mentioned enzymes, further fragments of vasopressin molecule were prepared. Amino groups were protected with benzoylcarbonyl or tert-butyloxycarbonyl groups, carboxyl groups as phenylhydrazides or methyl esters, and the cysteine sulfhydryl group as the benzyl derivate. The tyrosine hydroxyl was not protected.

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