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Mycalolide‐B, a novel and specific inhibitor of actomyosin ATPase isolated from marine sponge
Author(s) -
Hori Masatoshi,
Saito Shin-ya,
Shin Yutaka Z.,
Ozaki Hiroshi,
Fusetani Nobuhiro,
Karaki Hideaki
Publication year - 1993
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(93)81557-g
Subject(s) - sponge , atpase , chemistry , biochemistry , biophysics , biology , enzyme , botany
A toxin isolated from marine sponge, mycalolide‐B, inhibited smooth muscle contractions without changing cytosolic Ca 2+ levels. It also inhibited Ca 2+ ‐induced contraction in permeabilized smooth muscles. In native actomyosin prepared from chicken gizzard, mycalolide‐B inhibited superprecipitation and Mg 2+ ‐ATPase activity stimulated by Ca 2+ without changing myosin light chain phosphorylation. In the permeabilized muscle and native actomyosin preparation thiophosphorylated with ATPγS, mycalolide‐B inhibited ATP‐induced contraction and Mg 2+ ‐ATPase activity, respectively, in the absence of Ca 2+ . Mycalolide‐B also inhibited Mg 2+ ‐ATPase activity of skeletal muscle native actomyosin. Mycalolide‐B had no effect on calmodulin‐stimulated (Ca 2+ –Mg 2+ )‐ATPase activity of erythrocyte membranes. These results suggest that mycalolide‐B selectively inhibits actin—myosin interaction.