title: Chicken gizzard: relation between calcium-activated phosphorylation and contraction.
abstract: Of the proteins in mechanically disrupted chicken gizzard fibers (no functional sarcolemma) only the 20,000-dalton light chains of myosin underwent large Ca2+-and Sr2+-dependent changes in phosphorylation. Phosphorylation closely corresponded with the Ca2+- and Sr2+-activated tensions. Adenosine 5'-O (3'-thiotriphosphate) only in the presence of Ca2+ induced irreversible Ca2+-insensitive activation of tension and thiophosphorylation of the 20,000-dalton light chains, and blocked incorporation of 32P from [gamma-32P]adenosine triphosphate into the myosin light chains.
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002645:Chickens; D005895:Gizzard, Avian / Q000502:physiology*; D066298:In Vitro Techniques; D008970:Molecular Weight; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000502:physiology*; D009218:Myosins / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism
chemical_list: D011494:Protein Kinases; D009218:Myosins; D002118:Calcium