ISSN:
0749-503X
Keywords:
Saccharomyces cerevisiae
;
cysteine biosynthesis
;
metabolic regulation
;
cystathione γ-lyase
;
Life and Medical Sciences
;
Genetics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
Notes:
Regulation of the two enzymes in reverse trans-sulfuration was investigated in Saccharomyces cerevisiae. In wild-type strains, cystathionine γ-lyase, but not cystathionine β-synthase, was derepressed nearly 15-fold if cells were starved for both inorganic and organic sulfur compounds. In a met17 strain which is defective of O-acetylserine and O-acetylhomoserine sulfhydrylase, the same enzyme was derepressed if organic sulfur compounds were limited; the repressive effect was in the order of glutathione 〉 methionine 〉 cysteine. The repressive effect of methionine was not observed, however, in a cys2 cys4 strain which is deficient of serine O-acetyltransferase and cystathionine β-synthase, indicating that methionine itself is not the effector. The weak repressive effect of cysteine was attributed to inefficient uptake of this amino acid.Our observations indicate that cystathionine γ-lyase is the target of regulation in reverse trans-sulfuration and that cysteine is very likely to be the effector of this regulation.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/yea.320070809
