title: Schistosoma mansoni: inhibition of cercarial "penetration" proteases by components of mammalian blood.
abstract: 1. Normal human sera and plasma were fractionated in order to identify inhibitors of the "penetration" proteases of Schistosoma mansoni cercariae. 2. The main inhibitor, accounting for 90% of the total activity of serum, appears to be alpha 1-antitrypsin (alpha 1-AT) as identified by separation on DEAE-cellulose and Sephadex, by immunoelectrophoresis and by anticercarial protease activity of purified alpha 1-AT preparations. 3. The inhibition profiles of purified preparations of the 6 known serum antiproteases suggest that the parasite protease is similar to vertebrate chymotrypsin. 4. On a molar basis, the order of inhibitory activity against the cercarial protease is: alpha 1-AT = alpha 2-macroglobulin; C'-1-inactivator; alpha 1-antichymotrypsin. No inhibition was obtained with inter-alpha-inhibitor or antithrombin III.
mesh_terms: D000818:Animals; D002848:Chromatography, DEAE-Cellulose; D006801:Humans; D007122:Immunoelectrophoresis; D051379:Mice; D010447:Peptide Hydrolases / Q000378:metabolism*; D011480:Protease Inhibitors / Q000097:blood*; D011817:Rabbits; D012550:Schistosoma mansoni / Q000201:enzymology* / Q000502:physiology; D000515:alpha 1-Antitrypsin / Q000097:blood
chemical_list: D011480:Protease Inhibitors; D000515:alpha 1-Antitrypsin; D010447:Peptide Hydrolases