title: Inactivation of human plasma alpha 1-antichymotrypsin by microbial proteinases.
abstract: Incubation of human plasma alpha 1-antichymotrypsin with proteinases from various microbial sources resulted in the enzymatic inactivation of the inhibitor as determined by loss of inhibitory activity against alpha-chymotrypsin. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the reaction products indicated that intact alpha 1-antichymotrypsin (Mr 67000) had been converted to an inactive form (63000) by limited proteolysis. No stable proteinase/inhibitor complexes were detected, and no random proteolysis of the inactivated inhibitor occurred even after prolonged incubation with the proteinases. Metallo- and serine proteinases from several microbial sources all readily inactivated alpha 1-antichymotrypsin. Since alpha 1-antichymotrypsin is also an early stage acute phase reactant, its inactivation may be important in disrupting bodily defense mechanisms.
mesh_terms: D001419:Bacteria / Q000201:enzymology; D002918:Chymotrypsin / Q000037:antagonists & inhibitors* / Q000097:blood / Q000378:metabolism; D010450:Endopeptidases / Q000378:metabolism*; D006801:Humans; D007122:Immunoelectrophoresis; D013997:Time Factors; D000514:alpha 1-Antichymotrypsin
chemical_list: D000514:alpha 1-Antichymotrypsin; D010450:Endopeptidases; D002918:Chymotrypsin