Kallikrein modification with affinity to IgG present in higher amounts than normal in plasma from patients with Crohn's disease.
This study presents immunological and functional evidence to suggest that the activation of prekallikrein (PK) in human plasma yields two modifications of kallikrein. One of these modifications showed amidolytic properties strongly deviating from those registered for the main part of the enzyme. The substrates were S-2302, Bz-Pro-Phe-Arg-pNA, S-2366 and S-2222. In PAGE immunoblots the PK heavy chain mAb 13G11 was found to detect the kallikrein 85 kD double band and bands with mol. weights of about 152 and 135 kD. Such a 152 kD band could be removed together with an IgG fraction on a Protein G column. In this study the kallikrein identity was confirmed by an estimation of the levels obtained in amidolytic assays of mixtures of normal plasma and plasma deficient in FXI, which in immunological assays showed a PK level of 140-150%, of normal. A comparison in amidolytic assays of normal plasma and plasma from patients with Crohn's disease showed that patients' plasma contained a significantly higher level than normal of modified kallikrein. An IgG removal procedure removed all modified kallikrein, and did not affect ordinary kallikrein levels.
Department of Pharmacology, Institute of Pharmacy, University of Oslo, Blindern, Norway. kjell.briseid@farmasi.uio.no
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Briseid
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Johannesen
D000581:Amidohydrolases / Q000097:blood; D000915:Antibody Affinity; D003424:Crohn Disease / Q000097:blood* / Q000276:immunology; D004591:Electrophoresis, Polyacrylamide Gel; D005172:Factor XI / Q000032:analysis; D005174:Factor XII / Q000032:analysis; D006801:Humans; D007118:Immunoassay; D007074:Immunoglobulin G / Q000276:immunology*; D020842:Plasma Kallikrein / Q000032:analysis / Q000276:immunology* / Q000378:metabolism; D011288:Prekallikrein / Q000378:metabolism
D007074:Immunoglobulin G; D005174:Factor XII; D005172:Factor XI; D011288:Prekallikrein; D020842:Plasma Kallikrein; D000581:Amidohydrolases