Modulation by phosphorylation of glycogen phosphorylase‐sarcoplasmic reticulum interaction

FEBS Letters

Centeno, Francisco¹  Cuenda, Ana¹  Gutierrez-Merino, Carlos¹ 

[1] Departamento de Bioquimica y Biologia Molecular, Facultad de Ciencias, 06080 - Badajoz, Spain

关键词: Glycogen phosphorylase;    Sarcoplasmic reticulum;    Ca2+ + Mg2+-ATPase;    Fluorescein;    Regulation;    ATPase;    Ca2+ + Mg2+-ATPase;    EGTA;    ethyleneglycol-bis-β-aminoethyl ether)-N;    N;    N′;    N′-tetraacetic acid;    FITC;    fluorescein isothiocyanate;    IU;    μmols product per min per mg protein;    PLP;    pyridoxal-5′-phosphate;    SR;    sarcoplasmic reticulum;    Tes;    2-[(2-hydroxy-1;    1-bis-(hydroxymethyl) ethylaminel ethanosulfonic acid;    Tris;    tris(hydroxymethyl)-aminomethane;   

DOI  :  10.1016/0014-5793(91)80606-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Glycosen phosphorylase b at concentrations close to those found in skeletal muscle interacts with sarcoplasmic reticulum membranes, but not with liposomes made of lipids extracted from these membranes, and is inhibited upon binding to the membrane. The interaction of glycogen phosphorylase with the sarcoplasmic reticulum membrane is modulated by phosphorylation, for the a form of this enzyme shows a K _0.5 of interaction about 10-fold lower than the b form. Upon association to the membrane the fluorescence properties of the coenzymes of glycogen phosphorylase, pyridoxal-5′-phosphate, are strongly altered, for the fluorescence at 535 nm is partially quenched and the fluorescence at 415–420 nm increases. Using fluorescein labeled sarcoplasmic reticulum membranes we have found that average conformation of the Ca²⁺ + Mg²⁺-ATPaze is also altered on binding or phosphorylase b. In conclusion, the results reported in this paper suggest that glycogen phosphorylase and Ca²⁺ + Mg²⁺-ATPase directly interact under experimental conditions similar to those found in the sarcoplasm, and that this interaction is modulated by phosphorylation of the phosphorylase.

【 授权许可】

Unknown