Pyrrolidine and Putrescine Metabolism: y-Aminobutyraldehyde Dehydrogenase

A strain of Pseudomonas Jluorescens (ATCC 13430) was isolated which could utilize either pyrrolidine or putrescine as the sole source of carbon, nitrogen, and energy for growth. An investigation of the metabolism of pyrrolidine by this organism (1) suggested Al-pyrroline (I) as the first product of pyrrolidine catabolism followed by y-aminobutyric acid (III). Enzymes which were induced by growth on pyrrolidine and purified from extracts of the pseudomonad included a y-aminobutyric-glutamic transaminase (2) and a succinic semialdehyde dehydrogenase (3) leading to the formation of succinic semialdchyde and succinic acid, respectively, as sequential products of the utilization of y-aminobutyrate (III). The present report dealing with A’-pyrroline metabolism, records the isolation of a DPN-linked enzyme, y-aminobutyraldehyde dehydrogenase, involved in the oxidation of Al-pyrroline to y-aminobutyric acid (Reaction 1).