A cyclic reaction scheme illustrating carbohydrate metabolism

Potter, Van R.; Elvehjem, C. A.

doi:10.1021/ed015p89

Cited by 47 publications

(49 citation statements)

References 4 publications

(5 reference statements)

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“…1, stages II (succinate) and V (malonate). That the affinity points involve the two carboxylic acid groups is indicated by previous work (2,18,19 (Table I) and against cysteine and cystine (Table II) and now present evidence demonstrating protection of the enzyme by malonate against the action of quinone. (See Fig.…”

Section: Inhibition Of Succinoxidase By Sulfhydryl Compoundssupporting

confidence: 63%

“…Malonate is a strong inhibitor of the succinic dehydrogenase because it possesses two --COOH groups and a configuration very similar to that of succinate (18,19). Previous experiments with minced tissue or slices appear to be complicated by diffusion effects and require up to 0.025 ~r malonate to block the enzyme completely (20).…”

Section: Inhibition Of Succinoxidase By Sulfhydryl Compoundsmentioning

confidence: 99%

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Studies on the Mechanism of Hydrogen Transport in Animal Tissues

Potter

DuBois

1943

Journal of General Physiology

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110

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In 1938, Hopkins and coworkers (1, 2) showed that succinic dehydrogenase could be inactivated by oxidized glutathione (GSSG) and could be reactivated by reduced glutathione (GSH). They interpreted these results to mean that the active enzyme requires i n t a c t --S H groups and that when these are converted to the --S --S --form of the enzyme, the dehydrogenase is inactivated. Any assumption that the functioning of the enzyme involved an oscillation between the SH and the --S---S---form of the enzyme seemed to be definitely eliminated, however, by the fact that the --S --S --form could not be reduced by succinate. Thus the function of the SH group in succinic dehydrogenase has remained an unsolved problem.Although many proteins contain SH groups, very little is known about the structural relationship of the SH group to the rest of the molecule. Even in the case of egg albumin, in which the SH groups have received the most careful study, the mechanism by which the SH groups of native egg albumin are shielded from some sulfhydryl reagents and not from others remains obscure (3). In the case of succinic dehydrogenase, the presumptive SH group (1, 2) is associated with function, and the reaction of the protein with sulfhydryl reagents should be demonstrable on the basis of determinations of the amount of active enzyme remaining. Furthermore, since it is an oxidative enzyme, the measurement of oxygen uptake makes possible a continuous appraisal of the amount of active enzyme at any given moment. We have previously established the test conditions for the measurement of the activity of this enzyme (4, 5). The rate of oxygen uptake is a valid measure of succinic dehydrogenase activity in this system since cytochrome c and cytochrome oxidase, which are needed to complete the reaction with oxygen, are present in excess. The activity of the enzyme is so great under the proper conditions that the extraneous matter present in the enzyme preparation does not interfere with the study of the reaction.At present, inhibitor studies appear to constitute the only available means of establishing the presence of SH groups in succinic dehydrogenase and of determining their r61e in the function of the enzyme.

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Section: Inhibition Of Succinoxidase By Sulfhydryl Compoundssupporting

confidence: 63%

Section: Inhibition Of Succinoxidase By Sulfhydryl Compoundsmentioning

confidence: 99%

Studies on the Mechanism of Hydrogen Transport in Animal Tissues

Potter

DuBois

1943

Journal of General Physiology

Self Cite

110

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“…Its principal effect is the competitive inhibition of succinic dehydrogenase, first indicated by Quastel (198,199), with an affinity ratio of about 50/1 in favour of the malonate (200). Other carboxylic acids, such as oxalic, also inhibit succinic dehydrogenase, but are generally less efficient than malonic (84,201). They are all supposed to act by their twin carboxyl groups uniting with the dehydrogenase protein in the vicinity of the prosthetic thiol group, and so shielding it.…”

Section: Structural Inhibitorsmentioning

confidence: 99%

The Use of Respiratory Inhibitors

James¹

1953

Annu. Rev. Plant. Physiol.

157

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“…(Received for publication, February 2, 1942) Copper has been shown to have a definite effect in anemias due to a milk diet (11) and we have indicated a probable effect in experimental anemia due to blood loss (12,4). The experiments below show the effect of various doses of copper alone and combined with the standard dose of iron.…”

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confidence: 70%

Copper and Cobalt Related Hemoglobin Production in Experimental Anemia

Robscheit‐Robbins

Whipple

1942

Journal of Experimental Medicine

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Copper added to a standard diet often effects a moderate increase in hemoglobin production in anemia due to blood loss. The copper response is quite irregular in contrast to the iron response. In these dogs there is no lack of copper held in reserve stores (liver and spleen) so the reaction is not related to an actual deficiency of the element. An effect upon enzyme complexes related to globin and hemoglobin production is to be considered. Cobalt under similar conditions causes no stimulus to hemoglobin production, rather an inhibitory effect when more than minimal doses are given. The claim that cobalt causes a polycythemia in dogs receives no support from our experiments.

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A cyclic reaction scheme illustrating carbohydrate metabolism

Cited by 47 publications

References 4 publications

Studies on the Mechanism of Hydrogen Transport in Animal Tissues

Studies on the Mechanism of Hydrogen Transport in Animal Tissues

The Use of Respiratory Inhibitors

Copper and Cobalt Related Hemoglobin Production in Experimental Anemia

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