title: Activation of the first component of complement, C1: comparison of the effect of sixteen different enzymes on serum C1.
abstract: In this study, the effect of sixteen different enzymes on serum C1 and its subcomponents was investigated. The sixteen enzymes could be divided into three groups. First, enzymes which activate native C1: trypsin (optimal concentration 2.4 x 10(-4) mM); alpha-chymotrypsin (2.3 x 10(3) mM); thrombin (1.0 x 10(-5) mM); plasmin (1.9 x 10(-5) mM); elastase (5.8 x 10(-5) mM); pronase (3.0 x 10(-6) mM). All these enzymes are serine esterase and activate native serum C1 bound to EAC4 at the given concentration within 10 min at 30 degrees C. Furthermore, native C1 inhibited by a pentosanpolysulfoester, Sp54, is unable to undergo the internal activation but can be externally activated by the serine esterases. Second, enzymes which do not activate native C1 but result in a dose and time-dependent loss of C1 activity: collagenase; pepsin; carboxypeptidase B. Third, enzymes which have no effect on C1 and C1: Lysozyme; neuraminidase; beta-galactosidase; L-amino acid oxidase; arginase; streptokinase, and acetylcholinesterase.
mesh_terms: D000818:Animals; D002417:Cattle; D003166:Complement Activating Enzymes / Q000494:pharmacology; D003167:Complement Activation / Q000187:drug effects; D003172:Complement C1 / Q000378:metabolism*; D004306:Dose-Response Relationship, Immunologic; D005341:Fibrinolysin / Q000494:pharmacology; D006168:Guinea Pigs; D006801:Humans; D007700:Kinetics; D010426:Pentosan Sulfuric Polyester / Q000494:pharmacology; D010447:Peptide Hydrolases / Q000494:pharmacology*; D011817:Rabbits; D014357:Trypsin / Q000494:pharmacology
chemical_list: D003172:Complement C1; D010426:Pentosan Sulfuric Polyester; D003166:Complement Activating Enzymes; D010447:Peptide Hydrolases; D014357:Trypsin; D005341:Fibrinolysin