title: Ca2+ and Mg2+ protection against thermal denaturation of pancreatic elastase.
abstract: Thermal denaturation of porcine pancreatic elastase was studied by difference spectrophotometry. At 293 nm, and pH 8.0, the thermal transition of elastase occurs with a midpoint temperature (Tm) of (58.0 +/- 0.5) degrees C. Mg2+ and Ca2+ stabilize the native form in increasing the midpoint temperature of the transition, Ca2+ being more effective than Mg2+ in the 0-0.02 M concentration range. Furthermore, Ca2+ protects pancreatic elastase against the destabilizing effect of Cu2+. Whatever be the temperature between 40 degrees C and 55 degrees C, Ca2+ protects pancreatic elastase against loss of enzymatic activity.
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D003300:Copper / Q000037:antagonists & inhibitors / Q000494:pharmacology; D004795:Enzyme Stability / Q000187:drug effects; D008274:Magnesium / Q000494:pharmacology*; D008956:Models, Chemical; D010179:Pancreas / Q000201:enzymology*; D010196:Pancreatic Elastase; D011489:Protein Denaturation / Q000187:drug effects; D013552:Swine; D013696:Temperature
chemical_list: D003300:Copper; D010196:Pancreatic Elastase; D008274:Magnesium; D002118:Calcium