title: Myosin from abdominal flexor muscle in a crayfish, Procambarus clarki Girard.
abstract: 1. Crayfish (Procambarus clarki) myosin was obtained from abdominal flexor muscle. The Ca2+-ATPase activity of crayfish myosin was much lower than that of rabbit skeletal myosin. However, F-actin-activated Mg2+-ATPase of crayfish and its superprecipitation closely resembled those of rabbit skeletal myosin. This fact suggests that the ability of crayfish myosin to combine with F-actin is essentially the same as that of skeletal myosin, although the chemical structures of both the myosin  molecules when involved in their Ca2+-ATPast activity must be different from each other. 2. Crayfish and rabbit skeletal myosins were subjected to SDS-polyacrylamide gel electrophoresis. Crayfish myosin was found to have one heavy chain and two distinct light chain components (CF-gl and CF-g2), which have molecular weights of 18,000 and 16,000, respectively. These light chains correspond in molecular weight to the light chains (SK-g2 and SK-g3) in rabbit skeletal myosin. 3. CF-g1 could be liberated from the crayfish myosin molecule reacting with 5,5'-dithio-bis (2-nitrobenzoic acid), (Nbs2), without recovery of ATPase activity by the addition of DTT. These properties are equivalent to those of SK-g2 in rabbit skeletal myosin, although Nbs2-treated crayfish myosin did not recover its ATPase activity at all.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D003400:Astacoidea; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D007700:Kinetics; D046911:Macromolecular Substances; D008970:Molecular Weight; D009132:Muscles / Q000201:enzymology*; D009218:Myosins / Q000302:isolation & purification / Q000378:metabolism*; D011817:Rabbits; D013045:Species Specificity
chemical_list: D046911:Macromolecular Substances; D000251:Adenosine Triphosphatases; D009218:Myosins; D000252:Calcium-Transporting ATPases