The purpose of this project has been to test the postulate that high blood levels of pyruvate encountered in certain conditions such as steroid excess, diabetes mellitus under certain circumstances, and thiamine deficiency, are due to defective removal of pyruvate rather than excessive production. Specific methods of assay and direct studies of pyruvate tolerance were used. Intermediary carbohydrate metabolism was studied in a total of 109 subjects. The history of thiamine deficiency and of the concept of ensymes is outlined and the literature on pyruvate estimation and study in various clinical conditions is reviewed. Direct tests of pyruvate tolerance are discussed and the biochemistry if glucose breakdown is described. the history of analytical methodology for pyruvate is recounted.

Thesis (M. Sc.)--University of Canterbury, 2007. / Typescript (photocopy). "December 2007." Includes bibliographical references (leaves 130-134). Also available via the World Wide Web.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1963. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 180-186).

Recent investigations on the crude pigeon liver extracts have shown the presence of an enzyme which catalyzes the oxidative decarboxylation of malate to pyruvate and carbon dioxide. The name malic enzyme has been given to this enzyme to distinguish it from malic dehydrogenase. Under aerobic conditions the addition of ferrous sulfate resulted in inhibition of the action of malic enzyme. Subsequent investigation showed that the inhibition obaerved was not due to ferrous ions, but due to ferric ions which were contaminating the ferrous sulfate. It was also shown that under aerobic conditions ferrous ions were rapidly oxidized to ferric ions. Investigation of this oxidation of ferrous ions proved the reaction to be non-enzymatic, and to require the presence of malate at a pH of 5.0. The presence of pyruvate also caused oxidation of ferrous ions to ferric ions, but at a much slower rate. The oxidation of ferrous to ferric ions was inhibited by the addition of glutathione, It is thermodynamically possible that this observed inhibition was due to the oxidation of ferrous ions to ferric ions by the -SH group of glutathione. Three possible sites of inhibition exist. The conversion of DPN to TPN, the reduction of pyruvate to lactate, and the oxidative decarboxylation of malate. The first two reactions showed no inhibition in the presence of ferric ions while the latter was inhibited. Varying concentrations of malate indicated that the reaction is not one of competition for malate by the ferric ions and the malic enzyme. The gradual increasing of the enzyme concentration in a reaction flask inhibited with ferric ions reveals a point where the inhibition is overcome. Increasing the enzyme concentration beyond this point resulted in a constant increase in carbon dioxide evolution per unit enzyme increase up to the point where the availability of the substrate effected the rate of reaction. The addition of glutathione to the reaction inhibited with low concentrations of ferric ions caused a decrease in the observed inhibition. It is speculated that the affected enzyme possesses functional groups which are oxidized by ferric ions, inactivating the enzyme and limiting the reaction. In the presence of glutathione, the ferric ions would be reduced to ferrous ions causing a decrease in inhibition.

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Thesis supervisor: Mani Subramanian. Includes bibliographic references (p. 121-125).

Thesis (Ph.D.)--Michigan State University. Dept. of Chemistry, 2008. / Title from PDF t.p. (viewed on Mar. 30, 2009) Includes bibliographical references. Also issued in print.

Thesis (Ph. D.)--University of Wisconsin, 1942. / Typescript (carbon copy). eContent provider-neutral record in process. Description based on print version record. Includes bibliographies.

Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 130-144). Also available on the Internet.