Human plasma alpha 1- and alpha 2-thiol proteinase inhibitors strongly inhibit Ca-activated neutral protease from muscle.
Human plasma alpha 1- and alpha 2-thiol proteinase inhibitors (alpha 1,2TPIs) inhibited purified Ca-activated neutral protease (CANP) most strongly among a number of thiol proteinases tested. When CANP was added to plasma, it was also inhibited by alpha 2-macroglobulin (alpha 2M). At low CANP concentrations, CANP was bound mainly to alpha 1,2TPIs; and after saturation of alpha 1,2TPIs the additional CANP was bound to alpha 2M. These data suggested that a probable role of alpha 1,2TPIs is to neutralize the proteolytic activity of the CANP derived from the tissues in collaboration with alpha 2M.
D000818:Animals; D001798:Blood Proteins; D002154:Calpain; D002645:Chickens; D006801:Humans; D007700:Kinetics; D007704:Kininogens; D008970:Molecular Weight; D009132:Muscles / Q000201:enzymology*; D011480:Protease Inhibitors; D013552:Swine
D001798:Blood Proteins; D007704:Kininogens; D011480:Protease Inhibitors; C034138:alpha-thiol proteinase inhibitor; D002154:Calpain