A novel peptide inhibitor of the myosin ATPase from an Okinawan marine sponge

T Hiratsuka

doi:10.1016/s0021-9258(19)84691-4

Abstract

A substance which inhibits the myosin ATPase has been detected from an Okinawan marine sponge. The inhibitor has been isolated from the methanol-soluble extract of the sponge by gel filtration and hydrophobic chromatography. The isolated inhibitor is an amphipathic peptide, which is rich in Asp, Glu, Ser, and Gly, and devoid of Met and Trp. The molecular weight of the peptide is about 6300 as determined by gel filtration, amino acid analysis, and sodium dodecyl sulfate-gel electrophoresis. The peptide is a potent inhibitor not only for the K+-, Ca2+-, and Mg2+-ATPases of myosin, its subfragment-1, and actomyosin, but also for superprecipitation of actomyosin, inhibiting them completely in the range of 10-400 ng/ml. The peptide inhibitor may provide a useful tool to elucidate the structure-function relationship of the myosin ATPase.

Highlights

A substance which inhibits the myosin ATPase has localization of the ligand-binding sites in various biological been detected from an Okinawan marine sponge
We present a procedure for isolation of a peptide inhibitorfrom the marine sponge
-I - J cedure for the purification of a peptide from an Okinawan 90 marine sponge, which acts asa potent inhibitor of the myosin

Summary

A Novel Peptide Inhibitor of the Myosin ATPase from an Okinawan Marine Sponge*

Biological systems [13,23,24,25], we hoped to make use of a fluorescent inhibitor for the myosin ATPase to obtain further. Site-selective fluorescent probes, which bind noncovalently to specific sites of proteins, are useful for wan marine sponge was found to show inhibitoryactivity against myosin ATPase. The peak elution volume of each marker and the inhibitor was measured according to the absorbance at 280 nm and the inhibitory activity against the S-1ATPase, respectively. ATPase Measurements-The inhibitory activity of column eluates against myosin ATPase was assayed at 25 "C in a reaction mixture of 2.5 ml total volume, containing 10pl of the eluate, 0.005 mg/ml S1 , l mM ATP, 0.5 M KCl, 10 mM EDTA, and 20mM MOPS (pH 7.0). S-1. and actin were determined from the extinction coefficients

RESULTS

DISCUSSION

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