Methionine Limitation in Escherichia coli K-12 by Growth on the Sulfoxides of d -Methionine

Abstract

The synthesis and resolution of the diastereoisomers of d -methionine sulfoxide in high yield is described. Growth of two methionine auxotrophs (strains HfrC and AB1932) on the d -methionine sulfoxides is slower than on l -methionine, and the resultant cells are markedly derepressed for three enzymes of the methionine regulon (cystathionine synthetase, cystathionase, and S -adenosyl- l -methionine synthetase). Strain HfrC grows more rapidly on the sulfoxides and shows less derepression than strain AB1932. Although growth on d -methionine- d -sulfoxide is much slower than on d -methionine- l -sulfoxide (two- to threefold increase in division times), cells grown on d -methionine- l -sulfoxide generally have higher enzyme activities. The sulfoxides of d -methionine appear to provide a useful supplement to obtain methionine-limited growth in Escherichia coli .