Cuenda A, Centeno F, Gutierrez-Merino C
Departamento de Bioquimica y Biologia Molecular, Facultad de Ciencias, Badajoz, Spain.
FEBS Lett. 1991 Jun 3;283(2):273-6. doi: 10.1016/0014-5793(91)80606-4.
Glycogen 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 K0.5 of interaction about 10-fold lower than the b form. Upon association to the membrane the fluorescence properties of the coenzyme 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 the average conformation of the Ca2+ + Mg(2+)-ATPase is also altered on binding of phosphorylase b. In conclusion, the results reported in this paper suggest that glycogen phosphorylase and Ca2+ + Mg(2+)-ATPase directly interact under experimental conditions similar to those found in the sarcoplasm, and that this interaction is modulated by phosphorylation of the phosphorylase.
浓度接近骨骼肌中糖原磷酸化酶b与肌浆网膜相互作用，但不与从这些膜中提取的脂质制成的脂质体相互作用，并且在与膜结合时受到抑制。糖原磷酸化酶与肌浆网膜的相互作用受磷酸化调节，因为该酶的a形式显示出比b形式低约10倍的相互作用K0.5。与膜结合后，糖原磷酸化酶的辅酶磷酸吡哆醛的荧光特性发生强烈变化，因为535nm处的荧光部分猝灭，415-420nm处的荧光增加。使用荧光素标记的肌浆网膜，我们发现Ca2+ + Mg(2+)-ATP酶的平均构象在磷酸化酶b结合时也发生改变。总之，本文报道的结果表明，在类似于肌浆中发现的实验条件下，糖原磷酸化酶和Ca2+ + Mg(2+)-ATP酶直接相互作用，并且这种相互作用受磷酸化酶的磷酸化调节。
