Catabolism of l-Arginine by Pseudomonas aeruginosa

Abstract

SUMMARY: Pseudomonas aeruginosa is known to break down arginine by the arginine deiminase pathway. An additional pathway has now been found whereby arginine is converted to putres-cine with agmatine and N-carbamoylputrescine as intermediates. The following enzyme activities belonging to this pathway were detected in crude extracts: arginine decarboxylase (EC 4.1.1.19), which catalyses the release of CO₂ from arginine to give agmatine; agmatine deiminase (EC 3.5.3.12), which degrades agmatine to N-carbamoylputrescine; and N-carbamoylputrescine amidinohydrolase (EC 3.5.3.-), which then removes the ureido group of carbamoylputrescine. In crude extracts, arginine decarboxylase activity was stimulated by pyridoxal phosphate, Mg²⁺ and by the products of the catabolic pathway, putrescine and spermidine.