The Inducible Amine Dehydrogenase in Pseudomonas putida NP and its Role in the Metabolism of Benzylamine

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Abstract
SUMMARY: Pseudomonas putida NP utilizes benzylamine and other primary amines as the sole source of carbon, nitrogen and energy. Extracts of organisms grown on benzylamine and other amines contained an inducible amine dehydrogenase [amine:(acceptor) oxidoreductase (deaminating)]. The enzyme required either phenazine methosulphate, 2,6-dichlorophenolindophenol, ferricyanide or cytochrome c for activity; oxygen, FAD, FMN, NAD+ and NADP+ were not utilized. The substrate specificity of the amine dehydrogenase was independent of the amine utilized for growth; when cell-free extracts of organisms grown on benzylamine, n-propylamine or n-butylamine were subjected to polyacrylamide gel electrophoresis, a single band of enzymic activity was detected in an equivalent position in each gel. This indicated that an enzyme of broad specificity was involved in the deamination of these substrates. The amine dehydrogenase was heat labile; 97% of the initial activity was lost after incubation at 65 °C for 3 min. By isolating intermediates and demonstrating the requisite enzyme activities, it was shown that benzylamine was deaminated to benzaldehyde and further metabolized through benzoate and via the meta (or α-keto acid) pathway.