Decarboxylation of Neutral Amino Acids in Proteus vulgaris

Abstract

SUMMARY: Washed suspensions and cell-free extracts of Proteus vulgaris decarb- oxylate leucine, valine, norvaline, isoleucine, and α -amino- n -butyric acid. The system differs from most bacterial decarboxylases in being optimally active near pH 7 and in not requiring acid conditions for its formation. The system is adaptive (inducible); the presence of either leucine, valine or isoleucine will simultaneously induce decarboxylase activity against each of the five amino acids listed above. No additive effects were found when two amino acids were offered to the system simultaneously. Pyridoxal phosphate is required as coenzyme at least for valine and leucine decarboxylation ; the affinity between apo- and co-enzyme is greater during decarboxylation of valine than leucine.