Myosin isoenzymes enriched in either alkali 1 or alkali 2 light chains exhibited nearly identical maximum rates of ATP hydrolysis and similar apparent affinities for actin.
The presence of a specific alkali light chain does not significantly influence the maximum rate of ATP turnover by actomyosin under near-physiological ionic strength conditions.
Myosin isoenzymes, highly enriched in either alkali 1 or alkali 2 light chains have been prepared by light chain exchange in 4.7 M ammonium chloride, under conditions where there is minimal loss of ATPase activity. While the actin-activated ATPase measurements were complicated by a biphasic dependence on actin concentration, the two myosin isoenzymes behaved in a similar manner; at a variety of ionic strength conditions their maximum rates of ATP hydrolysis were nearly identical. Furthermore, under conditions where their Km values could be reliably determined, their apparent affinities for actin in the presence of ATP did not differ greatly. These results suggest that the presence of a particular alkali light chain does not influence the maximum rate of ATP turnover by actomyosin under ionic strength conditions approximating physiological.
Pope et al. (Mon,) reported a other. Myosin isoenzymes enriched in alkali 1 or alkali 2 light chains was evaluated on Maximum rates of ATP hydrolysis and apparent affinities for actin. Myosin isoenzymes enriched in either alkali 1 or alkali 2 light chains exhibited nearly identical maximum rates of ATP hydrolysis and similar apparent affinities for actin.