The major plasma kallikrein inhibitor in guinea pig plasma with contrapsin-like nature.
Kallikrein inhibitor in plasma (KIP) was purified, and the share in the kallikrein inhibitory capacity of guinea pig plasma was estimated by depletion of the inhibitory activity of KIP with anti-KIP IgG. And KIP was characterized the inhibitory activity using various proteases. The purified KIP exhibited a single band on SDS-gel electrophoresis and the molecular weight was 64,000. KIP inhibited plasma kallikrein dose-dependently and time-dependently, forming a complex with kallikrein with the molecular weight of 137,000. Since the kallikrein inhibitory capacity of guinea pig plasma was completely depleted by anti-KIP IgG that inactivated kallikrein inhibitory activity of KIP, KIP was likely to be the major kallikrein inhibitor in guinea pig plasma. KIP inhibited trypsin and elastase, but not chymotrypsin. The Inhibitory spectrum of KIP was different from the spectrum of each protease inhibitor in human plasma, but was similar to the spectrum of contrapsin in mouse plasma. These results indicated that guinea pig plasma had a different mechanism for kallikrein inhibition, compared with human plasma.
Imamura
T
T
Department of Allergy, Kumamoto University Medical School, Japan.
Kambara
T
T
D000595:Amino Acid Sequence; D000818:Animals; D000936:Antigen-Antibody Complex; D006168:Guinea Pigs; D007074:Immunoglobulin G; D007610:Kallikreins / Q000037:antagonists & inhibitors / Q000097:blood*; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010084:Oxidation-Reduction; D015843:Serpins; D013379:Substrate Specificity; D014361:Trypsin Inhibitors / Q000097:blood* / Q000302:isolation & purification
D000936:Antigen-Antibody Complex; D007074:Immunoglobulin G; D015843:Serpins; D014361:Trypsin Inhibitors; C033691:contrapsin; D007610:Kallikreins