title: Assay of complexed alpha 1-antichymotrypsin in plasma.
abstract: We introduce an assay to measure complexed alpha 1-antichymotrypsin in human plasma. The assay works on the principle that the target proteinase cathepsin G has a very high affinity to the surface of microtiter plates, even if these surfaces are blocked with albumin and Tween 20. alpha 1-Antichymotrypsin, when complexed to cathepsin G, is thus immobilized and can be detected with specific antibodies. The mean (SD) concentration of alpha 1-antichymotrypsin in 50 healthy individuals was 1.73 (0.58) nmol/L. The detection limit was 0.84 nmol/L. The results of the assay are linear to at least 14 nmol/L. We propose to use this assay for diseases in which increased turnover of alpha 1-antichymotrypsin or cathepsin G can be expected to clarify further the function of this enzyme-inhibitor system.
authors: Division of Hematology/Oncology and Clinical Immunology, Philipps Universität Marburg, Germany.
authors: H H
authors: HH
authors: Heidtmann
authors: K
authors: K
authors: Havemann
mesh_terms: D000328:Adult; D056649:Cathepsin G; D002403:Cathepsins / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000592:standards / Q000706:statistics & numerical data; D004800:Enzymes, Immobilized; D005260:Female; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012697:Serine Endopeptidases; D013997:Time Factors; D000514:alpha 1-Antichymotrypsin / Q000097:blood*
chemical_list: D004800:Enzymes, Immobilized; D000514:alpha 1-Antichymotrypsin; D002403:Cathepsins; D012697:Serine Endopeptidases; C534094:CTSG protein, human; D056649:Cathepsin G