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

K. Yamaguchi, M. Hirata, T. Ishimatsu, H. Kuriyama

Research output: Contribution to journalArticle

Abstract

1. 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.

Original languageEnglish
Pages (from-to)163-166
Number of pages4
JournalComparative biochemistry and physiology. C, Comparative pharmacology and toxicology
Volume92
Issue number1
Publication statusPublished - Jan 1 1989

All Science Journal Classification (ASJC) codes

  • Toxicology

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