title: Comparison of the effect of calcium(II) and manganese(II) ions on trypsin autolysis.
abstract: The effect of Mn2+ and Ca2+ ions on the rate of trypsin autolysis was studied at pH 7.0 and at 34.4-60.2 degrees C. For comparison, the kinetic constants of esterolytic activity of trypsin in the presence of the metal ion were determined at pH 7.4 and at 36 degrees and 40 degrees C. There was no significant difference in the rate of autolysis between Mn2+ and Ca2+ in the temperature range 34-47 degrees C, but at 56.8 degrees and 60.2 degrees autolysis was slightly more rapid in the presence of Mn2+. The Mn2+ or Ca2+ ion bound to trypsin is supposed to control the conformation and thereby the stability and the activity of the enzyme. The indirect effect of Mn2+ and Ca2+ is discussed on a structural basis of the enzyme molecule.
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002417:Cattle; D007700:Kinetics; D008345:Manganese / Q000494:pharmacology*; D013816:Thermodynamics; D014357:Trypsin / Q000378:metabolism*
chemical_list: D008345:Manganese; D014357:Trypsin; D002118:Calcium