원문정보
초록
영어
Yeast, Saccharomyces cerevisiae, produces hydrogen sulfide (H2S) as an undesirable by-product during alcoholic fermentation. Very low levels of H2S can be detected, so it can have a profound effect on final product quality. It is highly desirable to have yeast strains available for various fermented production that will not produce and release H2S. To confirm H2S producing proteins in Saccharomyces cerevisiae, we assayed the beta-replacement reaction activity with beta-mercaptoethanol and L-cysteine, which will form S-hydroxyethyl-L-cysteine and H2S. Formed H2S can easily be detected by the incubation with Pb-acetate that will make Pb-sulfide precipitation. When the crude extract of S. cerevisiae was incubated with beta-mercaptoethanol, L-cysteine and Pb-acetate, two proteins which made H2S on the Native-PAGE staining were detected. Because CYS4 gene deleted crude extracts gave only one H2S producing protein in the Native gel, cystathionine beta-synthase is one of the H2S producing protein. The other protein was identified as O-acetylhomoserine sulfhydrylase by MALDI-TOF mass analysis. We could produce CYS4 and Met 17 deficient yeast strain.