Trypsin complexed with alpha 1-proteinase inhibitor has an increased structural flexibility.
Mutant rat trypsin Asp189Ser was prepared and complexed with highly purified human alpha 1-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 alpha 1-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.
Kaslik
G
G
Department of Biochemistry, Eötvös University, Budapest, Hungary.
Patthy
A
A
Bálint
M
M
Gráf
L
L
D000595:Amino Acid Sequence; D000818:Animals; D001216:Asparagine; D002417:Cattle; D002845:Chromatography / Q000379:methods; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D011487:Protein Conformation; D051381:Rats; D012694:Serine; D014357:Trypsin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000515:alpha 1-Antitrypsin / Q000737:chemistry* / Q000378:metabolism
D000515:alpha 1-Antitrypsin; D012694:Serine; D001216:Asparagine; D014357:Trypsin