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R D SAGERS

Publications and source records attributed to R D SAGERS.

9 recordsLinked to original sources
PubMed1963

FAILURE OF ARSENATE TO UNCOUPLE THE PHOSPHOTRANSACETYLASE SYSTEM IN CLOSTRIDIUM ACIDIURICI.

Sagers, Richard D. (Brigham Young University, Provo, Utah), Moshe Benziman, and Sigrid M. Klein. Failure of arsenate to uncouple the phosphotransacetylase system in Clostridium acidiurici. J. Bacteriol. 86:978-984. 1963.-The conversion of pyruvate to acetyl phosphate by extracts of Clostridium acidiurici required coenzyme A (CoA), an electron-carrier system (ferredoxin and nicotinamide adenine dinucleotide), and a divalent metal. Other cofactors may be involved but are not presently defined. The metal activates the system transferring acetyl units between CoA and phosphate. Acetyl CoA could be generated from pyruvate or from acetyl phosphate, but in both cases arsenate failed to uncouple the high-energy acyl compounds. The rate of acetyl transfer between acetyl phosphate and CoA was markedly decreased by 0.005 m arsenate, but the generation of acetyl CoA from pyruvate was essentially unaffected until the arsenate concentration exceeded 0.02 m. Close agreement was observed between the amount of pyruvate utilized and the amount of acetyl phosphate formed, both in the presence and absence of arsenate. The CoA-dependent exchange of P(32)O(4) ( identical with) with acetyl phosphate proceeded at a rate approximately one-eightieth of the rate of acetylation of CoA, indicating an equilibrium value for the phosphotransacetylase reaction similar to that observed for Clostridium kluyveri. The failure of arsenate to uncouple the C. acidiurici enzyme may indicate a high degree of specificity in relation to the acetyl unit acceptor, giving preference to phosphate over arsenate.

Acetyl Coenzyme A↗
PubMed1962

An efficient, easily constructed cell homogenizing press.

An easily constructed, highly efficient cell homogenizing press is described which should be available to laboratories at moderate cost. The press allows the preparation of homogenates from up to 20 g of packed cell paste in a single batch without danger of damage to the press. Cell breakage and recovery of cell homogenates is accomplished at temperatures which maintain the material in the frozen state. The press may be assembled, disassembled, and cleaned with minimal effort.

Bacteriology↗
PubMed1962

Intermediary metabolism of Diplococcus glycinophilus. II. Enzymes of the acetategenerating system.

Klein, Sigrid M. (Brigham Young University, Provo, Utah) and Richard D. Sagers. Intermediary metabolism of Diplococcus glycinophilus. II. Enzymes of the acetate-generating system. J. Bacteriol. 83:121-126. 1962-The enzymatic steps in the conversion of glycine to acetate by Diplococcus glycinophilus were examined and the reaction rates of the individual steps compared with the maximal glycine fermentation rate by whole cells. Glycine is oxidatively cleaved to one-carbon units with the alpha carbon being transferred to tetrahydrofolate at the oxidation level of formaldehyde. The activated one-carbon unit is condensed with a second glycine molecule to form serine which is then deaminated to pyruvate. Pyruvate gives rise to acetyl units as acetyl coenzyme A and acetyl phosphate. The latter compound reacts with adenosine diphosphate to yield acetate and adenosine triphosphate, providing the main energy-yielding reaction in the fermentation. The enzyme systems discussed together with their specific activities (mumoles substrate acted upon per hr per mg protein) are as follows: serine aldolase, 9 to 12; serine dehydrase, 180; pyruvate-oxidizing and acyl unit-generating system, 96; phosphotransacetylase, 96; acetokinase, 3,600. The high activity of the acetokinase system may tend to pull the entire reaction series in the direction of acetate and adenosine triphosphate generation. In all cases the reaction rates of the individual enzyme systems were equal to or significantly greater than the over-all glycine fermentation rate by whole cells (9 mumoles per hr per mg protein). If coupled together, these enzymes could account for the fermentation of glycine to acetate, CO(2), and ammonia and could account for the conversion of 2-labeled glycine to doubly-labeled acetate as demonstrated in previous tracer studies.

Acetates↗