猪冠状动脉胞质溶胶部分中肌醇1,4,5-三磷酸3-激酶活性的钙离子依赖性

Ca2+ dependence of inositol 1,4,5-trisphosphate 3-kinase activity in the cytosol fraction of pig coronary artery.

Yamaguchi K, Hirata M, Ishimatsu T, Kuriyama H

Department of Pharmacology, Faculty of Medicine, Kyushu University, Fukuoka, Japan.

Comp Biochem Physiol C Comp Pharmacol Toxicol. 1989;92(1):163-6. doi: 10.1016/0742-8413(89)90220-x.

Abstract

The activity of inositol 1,4,5-trisphosphate 3-kinase in subcellular fractions of smooth muscles of the pig coronary artery was examined. 2. Incubation of [3H]inositol 1,4,5-trisphosphate (IP3) with muscle homogenates produced more polar 3H-radioactivity (probably as inositol 1,3,4,5-tetrakisphosphate, IP4) than IP3, in the Mg2+- and ATP-dependent manner, thereby indicating the presence of IP3 3-kinase activity in homogenates of the muscle. 3. Most of the kinase activity was present in the cytosol fraction. The enzyme activity was reversibly activated by Ca2+ with a half-maximal effective concentration of 2.5 x 10(-7) M. 4. The calmodulin antagonists, W-7 and chlorpromazine inhibited the Ca2+-activated enzyme activity.

摘要

对猪冠状动脉平滑肌亚细胞组分中的肌醇1,4,5-三磷酸3-激酶活性进行了检测。2. [3H]肌醇1,4,5-三磷酸（IP3）与肌肉匀浆一起孵育，以Mg2+和ATP依赖的方式产生了比IP3极性更强的3H放射性（可能是肌醇1,3,4,5-四磷酸，IP4），从而表明肌肉匀浆中存在IP3 3-激酶活性。3. 大部分激酶活性存在于胞质溶胶组分中。该酶活性可被Ca2+可逆激活，半数最大有效浓度为2.5×10(-7)M。4. 钙调蛋白拮抗剂W-7和氯丙嗪抑制Ca2+激活的酶活性。