Decarboxylation of Neutral Amino Acids in Proteus vulgaris

Abstract

Washed suspensions and cell-free extracts of P. vulgaris decarboxylate leucine, valine, norvaline, isoleucine, and [alpha]-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; the presence of either leucine, valine or isoleucine will simultaneously induce decarboxylase activity against each of the 5 amino acids listed above. No additive effects 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.