title: Inhibition spectra of the human pancreatic endopeptidases.
abstract: The present work describes the effect of seven naturally occurring proteinase inhibitors on the human pancreatic endopeptidases cationic trypsin, anionic trypsin, chymotrypsin I, chymotrypsin II, and protease E (an elastase-like protease). The inhibitors tested in order of their decreasing effectiveness were alpha-1-proteinase inhibitor (alpha-1-antitrypsin), lima bean trypsin inhibitor, soybean trypsin inhibitor, Bowman-Birk (soybean) inhibitor, Kunitz pancreatic trypsin inhibitor, porcine Kazal inhibitor, and chicken ovomucoid. The human trypsins demonstrated a higher degree of susceptibility to these inhibitors than did the chymotrypsins while human protease E showed remarkably little inhibition by any of these naturally occurring proteinase inhibitors except for alpha-1-proteinase inhibitor. The contribution of each of these proteolytic enzymes to the total proteolytic activity of crude extracts was also investigated using specific active-site directed reagents. These studies revealed that the trypsins constituted approximately 35% of the proteolytic activity while the chymotrypsins represent approximately 32% of the total proteolytic activity. Human protease E and possibly human pancreatic elastase are responsible for approximately 21% of this activity as measured on crude pancreatic extracts.
mesh_terms: D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002645:Chickens; D002918:Chymotrypsin / Q000037:antagonists & inhibitors*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007477:Ions; D010059:Ovomucin / Q000494:pharmacology; D010179:Pancreas / Q000201:enzymology*; D010196:Pancreatic Elastase / Q000037:antagonists & inhibitors; D010944:Plants; D011480:Protease Inhibitors; D013025:Glycine max; D013329:Structure-Activity Relationship; D013552:Swine; D014358:Trypsin Inhibitor, Bowman-Birk Soybean / Q000494:pharmacology; D014359:Trypsin Inhibitor, Kazal Pancreatic / Q000494:pharmacology; D014361:Trypsin Inhibitors / Q000494:pharmacology*; D000515:alpha 1-Antitrypsin / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D007477:Ions; D011480:Protease Inhibitors; D014358:Trypsin Inhibitor, Bowman-Birk Soybean; D014361:Trypsin Inhibitors; D000515:alpha 1-Antitrypsin; D010059:Ovomucin; D014359:Trypsin Inhibitor, Kazal Pancreatic; D002918:Chymotrypsin; D010196:Pancreatic Elastase