[Isolation and certain properties of minor protein P55 inhibiting myosin and actinomyosin ATPase activity]. / Vydelenie i nekotorye svoistva minornogo belka P55, ingibiruiushchego ATFaznuiu aktivnost' miozina i aktomiozina.

A method of minor protein P55 isolation from extract of soluble proteins of A-zone of the sarcomere from rabbit skeletal muscle is described. It is shown that this protein inhibits Ca2+-ATPase of myosin and Mg2+-ATPase of reconstructed actomyosin, but it does not affect superprecipitation of actomyosin. The molecular weight which is determined by mobility and its polypeptide chain polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate is about 35 000 dalton.