A new diploma in musculoskeletal medicine based on the pain model

Abstract

A glycine-resistant mutant, no. 18, which was not lysed by glycine, was obtained from an l-serine-producing mutant, S395 (temperature-sensitive, O-methylserine-resistant), of a facultative methylotroph, Pseudomonas MS31. The mutant stably produced l-serine from glycine. The properties of the enzymes involved in the synthesis and degradation of l-serine were investigated in the wild-type strain MS31 and the l-serine-producing mutants. Mutant derivation had no effect on the activities of methanol dehydrogenase or serine hydroxymethyltransferase, which are involved in l-serine synthesis. On the other hand, the activity of l-serine dehydratase (SDH), which degrades l-serine, was reduced in the mutants. Cobalt (Co2+) inhibited SDH activity and its addition (6.5 mM) to the l-serine production culture significantly stimulated l-serine accumulation up to 14.9 mg/ml. The results suggest that blocking of SDH is important for the efficient production of l-serine from glycine by methylotrophs.