Transaminations with l-glutamate and α-oxoglutarate in fresh extracts of animal tissues

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Abstract
Transamination reactions were studied in freshly obtained extracts of liver and kidney mainly from the rat. To facilitate unambiguous interpretation of results, preparations were washed free of endogenous substrates, particles by repeated sedimentation, soluble extracts by dialysis. Formation of phenylalanine, tyrosine and leucine from the corresponding [alpha]-keto acids and L-glutamate, with particles of rat liver were observed chromatographically. Transaminations with L-[alpha]-amino acids (other than alanine and aspartate) and a-oxoglutarate, and with the corresponding [alpha]-keto acids and L-glutamate, are associated with the sediment-able particles of fresh rat-liver and rat-kidney homogenates. Quantitative studies with a photodensitometer on paper chromatograms, and with L-glutamic decarboxylase, show that glutamate formation with rat-liver and rat-kidney preparations is more rapid than aerobic oxidation, for all L-[alpha]-amino acids tested. Values of Qt for trans-amination with [alpha]-oxoglutarate with some L-[alpha]-amino acids, in rat kidney and liver, are comparable with QNH3 or Qurea values for oxidative deamination in slices.