title: The reactive site of human inter-alpha-trypsin inhibitor is in the amino-terminal half of the protein.
abstract: Human inter-alpha-trypsin inhibitor has been found to inactivate human trypsin, chymotrypsin, neutrophil elastase and cathepsin G. The protein was cleaved into two major fragments without loss of activity by incubation with Serratia marcescens metalloproteinase, and these were separated by ion-exchange chromatography. Inhibitory activity was found in only one of the fragments, the amino-terminal sequence of which was found to be identical with that of the native protein, as well as with that reported earlier for the urinary trypsin inhibitor. It may thus be concluded that the reactive site of the inter-alpha-trypsin inhibitor is located in the amino-terminal region.
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D056649:Cathepsin G; D002403:Cathepsins / Q000037:antagonists & inhibitors; D002918:Chymotrypsin / Q000037:antagonists & inhibitors; D006801:Humans; D008666:Metalloendopeptidases; D010196:Pancreatic Elastase / Q000037:antagonists & inhibitors; D011480:Protease Inhibitors; D012697:Serine Endopeptidases; D012706:Serratia marcescens / Q000201:enzymology; D014357:Trypsin / Q000378:metabolism; D000515:alpha 1-Antitrypsin / Q000032:analysis*
chemical_list: D011480:Protease Inhibitors; D000515:alpha 1-Antitrypsin; D002403:Cathepsins; D012697:Serine Endopeptidases; D002918:Chymotrypsin; C534094:CTSG protein, human; D056649:Cathepsin G; D010196:Pancreatic Elastase; D014357:Trypsin; D008666:Metalloendopeptidases