Activation of the PCSM‐protein phosphatase by a Ca2+‐dependent protease

FEBS Letters

Goris, Jozef¹  Merlevede, Wilfried¹  Waelkens, Etienne¹ 

[1] Afdeling Biochemie, Faculteit Geneeskunde, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium

关键词: Polycation-stimulated protein phosphatase;    Phosphorylase;    a Inhibitor-1;    Ca2+-dependent protease Modulator protein (inhibitor-2);   

DOI  :  10.1016/0014-5793(85)80133-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The inhibitor-1 phosphatase but not the phosphorylase phosphatase activity of a newly discovered 250 kDa polycation-stimulated (PCS_M) protein phosphatase in rabbit skeletal muscle is increased up to 10-fold by a Ca²⁺-dependent protease. The enzyme-directed protease effect to which the PCS_H and PCS_L. phosphatases are insensitive was progressively lost during purification of the enzyme. This could be explained by either a slow conversion of the enzyme to an active form of the enzyme with a change in specificity, or the loss of a protease-sensitive inhibitor of the inhibitor-1 phosphatase activity, resulting in a PCS phosphatase characterized by its high inhibitor-1/phosphorylase a activity ratio. The Ca²⁺-dependent protease is completely inhibited by EGTA or leupeptin.

【 授权许可】

Unknown