title: In vitro digestion of actomyosin by extracts from tails of metamorphosing Xenopus laevis.
abstract: 1. Actomyosin purified from the tails of immature tadpoles of Xenopus laevis was degraded by exposure to low salt, 16,000 g supernatant extracts of involuting tadpole tails, as assayed by SDS polyacrylamide gel electrophoresis. 2. The proteolytic activity of the tail extracts was inhibited by ATP and leupeptin. Myosin (193,000 daltons) is initially cut to produce a 161,000 dalton fragment, then in a second step yielding 95,000 dalton fragments. 3. Both ATP and leupeptin inhibit the formation of these smaller fragments. 4. Ca2+ at approximately 100 microM stimulates early degradative steps.
mesh_terms: D000205:Actomyosin / Q000302:isolation & purification / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D008247:Lysosomes / Q000201:enzymology; D008675:Metamorphosis, Biological; D008970:Molecular Weight; D010447:Peptide Hydrolases / Q000378:metabolism; D014981:Xenopus / Q000254:growth & development*
chemical_list: D000205:Actomyosin; D010447:Peptide Hydrolases; D002118:Calcium