Hideo Katagiri

On the Metabolism of Organic Acids by Clostridium acetobutylicum: Part III. Purification and Properties of RacemiasePart IV. Mechanism of Racemiase ActionPart V. Further Studies on the Formation of RacemiasePart VI. Metabolism of Crotonic AcidPart VII. Reduction of Crotonic Acid

Racemiase, an enzyme which catalyzed racemization of lactic acids, was isolated from culture filtrate of Clostridium acetobutylicum by salting-out, and its purification was attained to about twenty-fold by treating with calcium phosphate gel. It was shown that racemiase requires for its full activity cofactors, pyridoxamine phosphate and ferrous ions. These substances were detected in the racemiasc preparation. Several other properties of racemiase were also investigated.

Studies on Transamination in Microoganisms

Transaminase reaction between l-Iysine and α-ketoglutaric acid was found in the cell-free extracts of Flavobacterium fuscum, Fl. flavescens and Achrolnobacter liquidum. The transaminase in the extract of Fl. fuscum was partially purified and some properties were investigated. The formation of glutamic acid proceeded stoichiometrically with disappearance of the substrates by transamination. d-Lysine and pyruvic acid, phenylpyruvic acid or oxaloacetic acid could not participate in this reaction as an amino donor and an amino acceptor, respectively. The activity of the transaminase was inhibited by addition of penicillamine. As the keto analogue of l-lysine did not react with 2,4-dinitrophenylhydrazine to form a hydrazone, but reacted with o-aminobenzaldehyde and p-dimethylaminobenzaldehyde to produce respectively unique color, it was suggested that the keto analogue was present in a fom of a cyclic compound containing a piperidine ring.

Microbiological Studies of Coli-aerogenes Bacteria: Part XVI. Enzymic Reduction of Glyoxylate to Glycollate by Coupling with Dehydrogenases of Hexose Monophosphate Shunt Pathway

The presence of glucose-6-phosphate markedly stimulated the anaerobic utilization of glyoxylate by either cell-free extracts or partially purified enzyme preparations of coli-aerogenes bacteria. The enzymic reduction of glyoxylate to glycollate was found to occur in the presence of TPN with the following substrates; glucose-6-phosphate, glucose plus ATP, gluconate plus ATP, glucose-1-phosphate or malate. The data indicated that the reduction of glyoxylate to glycollate was coupled to the oxidation of glucose-6-phosphate via the hexose monophosphate shunt pathway. It was propounded that the operation of the hexose monophosphate oxidative pathway might be controlled by TPN-linked glyoxylic reductase, and the mechanisms of enzymic regulation in microbial respiration were also discussed.

Microbiological Studies of Coli-aerogenes Bacteria: Part X. Various Factors Influencing α-Ketoglutarate-FermentationPart XI. Influence of the Amount of Available Oxygen upon α-Ketoglutarate-fermentation

α-Ketoglutarate was formed from the various carbohydrates including lactose, maltose, sucrose, d-glucose, d-fructose, d-galactose, d-mannose, d-mannitol, l-rhamnose, d-xylose, l-arabinose and glycerin. The influence of pH of the reaction mixture were tested, and inorganic phosphate was observed to be indispensable for α-ketoglutarate-fermentation. A cell of E. coli grown statically on glucose was found to reveal an ability of producing α-ketoglutarate under aerobic conditions. Optically dextro lactic acid was potent in the formation of a-ketoglutaric acid. The following reagents revealed the inhibiting effect on α-ketoglutarate-fermentation; CuSO4, AgNO3, iodoacetate, 2, 4-dinitrophenol, NaN3, 3-sulfanilamido-6-methoxypyridazine and arsenite, while, kanamycin and 8-azaguanine has no inhibiting effect. When E. coli was grown in a glucose-medium, a small supply of air increased the yield of acetate against decreasing α-ketoglutarate.

On the Metabolism of Organic Acids by Clostridium acetobutylicum: Part I. Formation of Lactic Acid and RacemiasePart II. Lactic Acid Metabolism and Relating Role of Racemiase

Authors confirmatively observed the phenomena that in adequate conditions, the mode of acetone-butanol fermentation could be converted into homo-lactic acid fermentation, and that the formation of “Racemiase” (lactic acid racemiase) was intensified through the appropriate lactate level in growing culture of the bacterium, Clostridium acetobutylicum.Furthermore in this series of the papers, the possible role of “Racemiase” in the lactic acid metabolizing sequence was suggested, and the chemical properties of “Racemiase” as well as the mechanism of enzymatic racemization of lactic acid were investigated. The metabolism of several organic acids were also discussed in connection with the fermentation pathway of this organism.

Microbiological Studies of Coli-aerogenes Bacteria: Part VII. Degradation of CitratePart VIII. The Occurrence of Isocitritase and CitritasePart IX. On the Mechanism of Assimilation of Ammonia

The cell-free extracts of coli-aerogenes produced glyoxylate and succinate in addition to pyruvate and α-ketoglutarate when incubation was carried out with a citrate-medium. The fresh cell-extracts possessed a very poor ability to produce α-ketoglutarate from citrate, but the addition of coenzyme II (TPN) to the reaction mixtures brought about an increase in the yield of α-ketoglutarate. The degradation of citrate by the intact (washed), dried and ground cells of the bacteria also resulted in an accumulation of glyoxylate in the external medium in which semicarbazide was present. It was suggested that the concentration of coenzyme II within the bacterial cells was relatively low, so that coenzyme II-dependent isocitric dehydrogenase was not operative at such a high rate enough to effect the complete removal of citrate. The bacterial cells revealed a high potency of producing α-ketoglutarate from pyruvate or succinate under aerobic conditions. It was indicated that the major breakdown of citrate by the cel...

2. Studies on Lactic Acid Fermentation: Part 1. Metabolism of Pyruvic Acid by Hetero-type Lactic Acid Bacteria

The metabolism of pyruvate by hetero-fermenters was found to vary according to experimental conditions; acetic acid formation was increased under aerobic conditions, while anaerobically acetoih formation was accelerated.When pyruvate was added to the growing culture during the early stage of growth, it was reduced to lactic acid, while acetoin was obtained from pyruvate when it was added during the later stage of the growing culture.No relationship of acetaldehyde to acetoin formation was ascertained, and no evidence was obtained on ethanol formation from pyruvate.