title: The binding of actin to phosphorylated and dephosphorylated myosin.
abstract: The binding of actin to myosin containing phosphorylated and dephosphorylated light chains (LC2) was investigated by studying the influence of actin on Mg2+- and K+-stimulated ATPase of phosphorylated and dephosphorylated myosin and by comparing the influence of PPi on actomyosin formed from pure actin and phosphorylated or dephosphorylated myosin. The concentration of actin producing inhibition of one half of myosin K+-ATPase activity was 4.1 micro M and 7.7 micro M for phosphorylated and dephosphorylated myosin, respectively. Actomyosin formed from dephosphorylated myosin dissociated at lower PPi concentration than did that from the phosphorylated form. The extrapolated values of Km obtained from studies of the influence of actin on Mg2+-ATPase activity of dephosphorylated myosin were about twice as high as for the phosphorylated form. Thus, the affinity of phosphorylated myosin for actin was significantly higher under conditions studied.
mesh_terms: D000199:Actins / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D027682:Cation Transport Proteins; D007700:Kinetics; D008274:Magnesium / Q000378:metabolism; D009218:Myosins / Q000378:metabolism*; D010766:Phosphorylation; D011817:Rabbits
chemical_list: D000199:Actins; D027682:Cation Transport Proteins; D000251:Adenosine Triphosphatases; C022761:potassium transporting ATPase; D009218:Myosins; D008274:Magnesium