Trypsin Complexed with α1-Proteinase Inhibitor Has an Increased Structural Flexibility
Mutant rat trypsin Asp189 Ser was prepared and complexed with highly purified human α1 -proteinase inhibitor. The complex formed was purified to homogeneity and studied by N-terminal amino acid sequence analysis and limited proteolysis with bovine trypsin. As compared to uncomplexed mutant trypsin the mutant enzyme complexed with α1 -proteinase inhibitor showed a highly increased susceptibility to enzymatic digestion. The peptide bond selectively attacked by bovine trypsin was identified as the Arg117 — Val118 one of trypsin. The structural and mechanistic relevance of this observation to serine proteinase-substrate and serine proteinase-serpin reactions are discussed.
KeywordsLimited Proteolysis Serine Proteinase Action Bovine Pancreatic Trypsin Inhibitor Bovine Trypsin Porcine Pancreatic Elastase
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