Open AccessPhosphorylation of yeast hexokinases
Author(s) -
VOJTEK Anne B.,
FRAENKEL Dan G.
Publication year - 1990
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1990.tb15585.x
Subject(s) - hexokinase , phosphorylation , protein subunit , serine , saccharomyces cerevisiae , biochemistry , immunoprecipitation , threonine , kinase , yeast , protein kinase a , biology , enzyme , chemistry , glycolysis , gene
We show by the use of 32 P‐labeling in vivo that hexokinase 2 and hexokinase 1 in Saccharomyces cerevisiae are phosphoproteins. The highest labeling was after incubation in medium with a low concentration of glucose, when labeling appears to be predominant even without use of immunoprecipitation. The nature of the modification is not known, but it has properties consistent with a phosphomonoester of serine or threonine. The cAMP‐dependent protein kinase plays a negative role in hexokinase phosphorylation, in that there was reduced labeling in strains ( bcyl ) lacking a regulatory subunit, and increased labeling during growth with high concentrations of glucose in a strain attenuated in the catalytic subunit ( tpkl w1 ). The function of the modification is not known, but there was a correlation between the extent of labeling and the expression of kinase‐dependent high‐affinity glucose uptake.