Novel heparin‐activated protein kinase activity in rabbit skeletal muscle

FEBS Letters

Ahmad, Zafeer¹  DePaoli-Roach, Anna A.¹  Roach, Peter J.¹ 

[1] Department of Biochemistry, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46223, USA

关键词: Protein kinase;    Heparin Glycogen synthase;    Rabbit muscle;   

DOI  :  10.1016/0014-5793(85)80199-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

A heparin-activated protein kinase has been identified in rabbit skeletal muscle. The enzyme, which had a native molecular mass of 70 kDa as judged by gel filtration, was stimulated 3- to 5-fold by heparin, halfmaximally at 3 heparin. The stimulation by heparin was not reproduced by other polyanions such as polyaspartate and polyglutamate. The protein kinase was detected by its ability to phosphorylate glycogen synthase; it was ineffective in phosphorylating caseins, phosvitin, histone, or phosphorylase. Glycogen synthase was phosphorylated to a stoichiometry of 0.7–0.8 phosphates/subunit, exclusively at serine residues located in the COOH-terminal CNBr-fragment of the subunit, with a corresponding reduction in the -/+ glucose-6P activity ratio from 0.96 to 0.43. The activity of the protein kinase was unaffected by the presence of Ca²⁺ and/or phospholipid, cyclic AMP or heat-stable inhibitor protein of cyclic AMP-dependent protein kinase. The enzyme was inhibited about 60% by the presence of glycogen, half-maximal effect at 25 . The heparin-activated protein kinase is clearly distinguishable from other known glycogen synthase kinases.

【 授权许可】

Unknown