EVIDENCE FOR THE INVOLVEMENT OF SERINE TRANSHYDROXYMETHYLASE IN SERINE AND GLYCINE INTERCONVERSIONS IN SALMONELLA TYPHIMURIUM

[摘要] Salmonella typhimurium can normally use glycine as a serine source to support the growth of serine auxotrophs. This reaction was presumed to occur by the reversible activity of the cnzyme, serine transhydroxymethylase (E. C. 2. 1. 2. 1; L-serine: tetrahydrofolic-5, 10 transhydroxymethylase), which is responsible for glycine biosynthesis. However, this enzyme had not been demonstrated to be solely capable of synthesizing serine from glycine in vivo. The isolation and characterization of a mutant able to convert serine to glycine but unable to convert glycine to serine supports the conclusion that a single enzyme is involved in this reversible interconversion of serine and glycine. The mutation conferring this phenotype was mapped with other mutations affecting serine transhydroxymethylase ( glyA ) and assays demonstrated reduced activities of this enzyme in the mutant.

[学科分类] 医学（综合）