Mycalolide‐B, a novel and specific inhibitor of actomyosin ATPase isolated from marine sponge

FEBS Letters

Karaki, Hideaki¹  Fusetani, Nobuhiro²  Saito, Shin-ya¹  Hori, Masatoshi¹  Ozaki, Hiroshi¹  Shin, Yutaka Z.¹ 

[1] Department of Veterinary Pharmacology, Faculty of Agriculture, The University of Tokyo, Bunkyo-ku, Tokyo 113, Japan;Department of Marine Biochemistry, Faculty of Agriculture, The University of Tokyo, Bunkyo-ku, Tokyo 113, Japan

关键词: Mycalolide-B;    Marine sponge;    Actomyosin inhibitor;    Smooth muscle;    Permeabilized muscle;    Skeletal muscle;    DTE;    dithioerythritol;    DTT;    dithiothreitol;    DFP;    diisopropylfluorophosphate;    EGTA;    ethylene glycol bis(β-aminoethylether)-N;    N;    N′;    N′-tetraacetic acid;    fura-2/AM;    acetoxymethyl ester of fura-2;    MLC;    myosin light chain;    PSS;    physiological salt solution;    TCA;    trichloroacetic acid;    Tris;    tris[hydroxymethyllaminomethane;   

DOI  :  10.1016/0014-5793(93)81557-G

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

A toxin isolated from marine sponge, mycalolide-B, inhibited smooth muscle contractions without changing cytosolic Ca²⁺ levels. It also inhibited Ca²⁺-induced contraction in permeabilized smooth muscles. In native actomyosin prepared from chicken gizzard, mycalolide-B inhibited superprecipitation and Mg²⁺-ATPase activity stimulated by Ca²⁺ without changing myosin light chain phosphorylation. In the permeabilized muscle and native actomyosin preparation thiophosphorylated with ATPγS, mycalolide-B inhibited ATP-induced contraction and Mg²⁺-ATPase activity, respectively, in the absence of Ca²⁺. Mycalolide-B also inhibited Mg²⁺-ATPase activity of skeletal muscle native actomyosin. Mycalolide-B had no effect on calmodulin-stimulated (Ca²⁺–Mg²⁺)-ATPase activity of erythrocyte membranes. These results suggest that mycalolide-B selectively inhibits actin—myosin interaction.

【 授权许可】

Unknown