Human Platelet Actin

Abstract
Human blood platelet action was purified using 30% sucrose to extract actomyosin and KI to dissociate actomyosin and to depolymerize actin. Pure actin thus obtained resembles skeletic muscle actin in its polymerization properties, CD [circular dichroism] spectra and ability to activate myosin Mg2+-ATPase. Isoelectric focusing gel analysis shows that human blood platelet actin exists in .beta. and .gamma. forms. The ratio of .beta. to .gamma. forms is 5:1 in purified actin, whole cell extract and in all fractions studied.