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Properties of calponin isolated from sheep aorta thin filaments
Author(s) -
Steven B. Marston
Publication year - 1991
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(91)80862-w
Subject(s) - calponin , caldesmon , tropomyosin , calmodulin , actin , chemistry , protein filament , biophysics , microbiology and biotechnology , biochemistry , biology , enzyme
Calponin, a 35 kDa actin‐binding protein, was shown to be a normal component of ‘native’ thin filaments prepared from sheep aorta. Actin, tropomyosin, caldesmon and calponin were present in molar ratios 14 : 2 : 1 : 0.9. Calponin was isolated from thin filaments in yield 0.5 mg/100 mg thin filament protein. Calponin inhibited actomyosin ATPase up to 85%, half maximal at 0.2 calponin/actin. Inhibition did not depend on tropomyosin, Ca 2+ or Ca 2+ ·calmodulin. Caldesmon inhibited actomyosin with a 10‐fold greater potency than calponin in the presence of tropomyosin and inhibition could be reversed by Ca 2+ ·calmodulin under certain conditions. Calponin had no effect on caldesmon inhibition or the reversal of inhibition.