Isolation and purification of actomyosin ATPase from mammalian brain

A simple technique for the isolation and purification of mammalian brain actomyosin, based on extraction of whole brains in low ionic-strength buffer, is described. The final preparation of brain actomyosin is obtained in good yield, has relatively high K+-EDTA and Ca2+-ATPase activities, and is substantially free of other ATPases and tubulin. The preparation is useful for initial enzymatic studies and/or as an enrichment step toward purification of the individual protein components. The Mg2+-ATPase and K+-EDTA ATPase activities are strongly inhibited by the sulfhydryl blocking reagent, pHMB. Interaction between the actin and myosin components can be demonstrated. Brain actomyosin had a distinct electrophoretic profile and enzymatic activity when compared with smooth muscle actomyosin from the aorta.