[Vitamin B 12 dependent methionine biosynthesis in pseudomonas aeruginosa]. / Vitamin B12-ABHANGIGE Methioninbiosynthese bei Pseudomonas aeruginosa

ABSTRACT

Among methionineless mutants of Pseudomonas aeruginosa strain PAO lacking the ability of methylating homocysteine we found two different types One of them responding to methionine only, the other one to methionine or vitamin B12 alternatively. That means that P. aeruginosa PAO as well as other B12-producing bacteria (with one exception Aerobacter aerogenes) use only the B12 pathway (metH) for methionine synthesis. The effect of some cys-auxotrophs equally growing on vitamin B12 as described by Calhoun and Feary (1969) was confirmed for P. aeruginosa PAO by our mutants. In a P. aeruginosa strain of other origin, PAE, neither met- nor cys-mutants responding to B12 have been found, although strain PAE as well as strain PAO excessively synthesize B12.