title: Effect of divalent cations on the proteolysis of vertebrate and invertebrate muscle myosin.
abstract: Analysis by SDS-polyacrylamide gel electrophoresis of the products of alpha-chymotryptic digestion of lobster abdominal muscle myosin has shown that the presence or absence of Ca2+ during proteolysis does not have a major influence on the site of cleavage of the parent molecule, as it does for proteolysis of vertebrate muscle myosin. By following H+ liberation on the pH-stat during proteolysis, it has been found that the divalent cation only suppresses digestion of lobster myosin by about 15% as compared with proteolysis in the absence of Ca2+. Additionally, the subfragment-1-like species made by alpha-chymotryptic digestion of lobster myosin at low ionic strength is much more susceptible to degradation by trypsin than is vertebrate muscle myosin sub-fragment-1, in accordance with the relative susceptibilities of the parent molecules to similar degradation.
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002645:Chickens; D002918:Chymotrypsin / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008970:Molecular Weight; D009132:Muscles / Q000032:analysis*; D009218:Myosins; D008121:Nephropidae; D011817:Rabbits; D013045:Species Specificity; D014357:Trypsin / Q000378:metabolism*
chemical_list: D002918:Chymotrypsin; D014357:Trypsin; D009218:Myosins; D002118:Calcium