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E B COLLINS

Publications and source records attributed to E B COLLINS.

12 recordsLinked to original sources
PubMed1963

ROLES OF CITRATE AND ACETOIN IN THE METABOLISM OF STREPTOCOCCUS DIACETILACTIS.

Harvey, R. J. (University of California, Davis), and E. B. Collins. Roles of citrate and acetoin in the metabolism of Streptococcus diacetilactis. J. Bacteriol. 86:1301-1307. 1963.-Streptococcus diacetilactis was unable to use citrate as a source of energy for growth, but the addition of citrate to a lactose-containing medium increased the specific growth rate 35%. Besides serving as the precursor of acetoin, some of the pyruvate formed from citrate was incorporated into cell material, primarily into lipids. A constant fraction of the weight of new cells was synthesized from the pyruvate formed from citrate. The rate of entry of citrate into cells was independent of the growth rate, and the usual result was that more pyruvate was formed from citrate than was required for cell synthesis. All excess pyruvate was converted to acetoin. Thus, acetoin formation acts as a detoxification mechanism, a means of removing intracellular pyruvate not required for synthesis of cell material.

Acetoin↗
PubMed1962

Citrate transport system of Streptococcus diacetilactis.

Harvey, R. J. (University of California, Davis) and E. B. Collins. Citrate transport system of Streptococcus diacetilactis. J. Bacteriol. 83:1005-1009. 1962.-The uptake of citrate by Streptococcus diacetilactis is mediated by a transport system that was distinguished from passive diffusion by inducibility and kinetics of uptake. In these characteristics the system is similar to the beta-galactoside permease of Escherichia coli. The citrate transport system of S. diacetilactis differs from beta-galactoside permease by requiring metabolic energy for operation under conditions that do not permit intracellular accumulation of the substance transported.

Biological Transport↗
PubMed1961

Role of citritase in acetoin formation by Streptococcus diacetilactis and Leuconostoc citrovorum.

Harvey, R. J. (University of California, Davis) and E. B. Collins. Role of citritase in acetoin formation by Streptococcus diacetilactis and Leuconostoc citrovorum. J. Bacteriol. 82:954-959. 1961.-Cell-free extracts of Streptococcus diacetilactis and Leuconostoc citrovorum converted citrate to acetate, oxalacetate, pyruvate, carbon dioxide, and acetoin. The products, stoichiometry, and cofactor requirements of the citrate-splitting reaction were identical to those reported for citritase. Coenzyme A was not required; the reaction was stimulated by magnesium or manganous ions, and inhibited by calcium ions. In S. diacetilactis the enzyme is constitutive; it has been found inducible in all other organisms that have been studied. Ten strains of S. diacetilactis, three strains of Leuconostoc, and one strain of S. liquefaciens contained the enzyme; 21 strains of S. cremoris and 3 strains of S. lactis did not. Cell-free extracts of S. diacetilactis and L. citrovorum converted pyruvate to acetoin and carbon dioxide in the presence of manganous ions and thiamine pyrophosphate.

Acetates↗