Accumulation of L-cystathionine by an Escherichia coli mutant deficient in cystathionine beta-lyase.

Abstract An Escherichia coli mutant deficient in cystathionine β-lyase was found to accumulate a substance detectable by ninhydrin reaction and chloride platinic acid reaction in its cells (rarely in the culture supernatant) when cultured with a limited amount (50–200 μg/ml) of l -methionine to support the growth. The product was released by freezing treatment and isolated by ion-exchange chromatography (cation exchange resin: Daiaion SK1B). It was identified as l -cystathionine by liquid chromatography-mass spectrometry, 13 C- and 1 H-nuclear magnetic resonance analyses and high-performance liquid chromatography (as its 2,3,4,6-tetra- O -acetyl-β- d -glucopyranosyl isothiocyanate derivative).