Nakamura A, Shiomi H
Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Japan.
Peptides. 1991 Nov-Dec;12(6):1375-7. doi: 10.1016/0196-9781(91)90222-b.
A phosphorylated analogue of DSIP at Ser7 has been shown to exist endogenously by immunochemical studies. An enzyme which could phosphorylate DSIP has not yet been identified. In the present study, we examined DSIP as a substrate for in vitro phosphorylation by casein kinase II. DSIP was phosphorylated by the enzyme with apparent Km and Vmax values of 20 mM and 90.9 nmol/min/mg protein, respectively. Both ATP and GTP were utilized as phosphoryl donors. Phosphorylation of DSIP was inhibited by heparin and enhanced by spermine. These results demonstrate that DSIP can serve as a possible substrate for casein kinase II in vitro.
免疫化学研究表明，丝氨酸7位磷酸化的DSIP类似物可内源性存在。尚未鉴定出能使DSIP磷酸化的酶。在本研究中，我们检测了DSIP作为酪蛋白激酶II体外磷酸化的底物。该酶使DSIP磷酸化，其表观Km和Vmax值分别为20 mM和90.9 nmol/分钟/毫克蛋白。ATP和GTP均用作磷酰基供体。肝素可抑制DSIP的磷酸化，而精胺可增强其磷酸化。这些结果表明，DSIP在体外可能是酪蛋白激酶II的底物。
