Vojtek A B, Fraenkel D G
Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, MA 02115.
Eur J Biochem. 1990 Jun 20;190(2):371-5. doi: 10.1111/j.1432-1033.1990.tb15585.x.
We show by the use of 32P-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 (bcy1) lacking a regulatory subunit, and increased labeling during growth with high concentrations of glucose in a strain attenuated in the catalytic subunit (tpk1w1). 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.
我们通过体内32P标记表明，酿酒酵母中的己糖激酶2和己糖激酶1是磷蛋白。最高标记出现在低浓度葡萄糖培养基中孵育后，此时即使不使用免疫沉淀，标记似乎也占主导。修饰的性质尚不清楚，但它具有与丝氨酸或苏氨酸磷酸单酯一致的特性。cAMP依赖性蛋白激酶在己糖激酶磷酸化中起负作用，因为在缺乏调节亚基的菌株（bcy1）中标记减少，而在催化亚基减弱的菌株（tpk1w1）中高浓度葡萄糖生长期间标记增加。修饰的功能尚不清楚，但标记程度与激酶依赖性高亲和力葡萄糖摄取的表达之间存在相关性。
