title: A universal calibrator for prostate specific antigen (PSA).
abstract: We describe for the first time a protocol to purify an in vitro made PSA-ACT complex to apparent homogeneity by using a combination of gel filtration and ion-exchange chromatography. The purity of the PSA-ACT complex was confirmed by gel electrophoresis and Western blot. Purification of the PSA-ACT complex was highly reproducible. An extinction coefficient of 1.0 and 280 nm (L x g-1 x cm-1) was assigned to the PSA-ACT complex based on amino acid analysis. Molecular weight was assigned by taking cDNA of ACT (plus 26% carbohydrate) and the molecular weight of PSA (28,430) which totals 89,280. Two common calibrators were made consisting of 100% PSA-ACT complex and/or 90% PSA-ACT complex plus 10% free PSA (90:10 calibrator). The 90:10 calibrator is recommended as a universal calibrator for the international standardization of PSA immunoassays.
authors.affiliation: Department of Urology, Medical Center, Stanford University, California, USA.
authors.forename: A F
authors.initials: AF
authors.lastname: Prestigiacomo
authors.forename: Z
authors.initials: Z
authors.lastname: Chen
authors.forename: T A
authors.initials: TA
authors.lastname: Stamey
mesh_terms: D006801:Humans; D007159:Immunologic Tests / Q000592:standards*; D008297:Male; D017430:Prostate-Specific Antigen / Q000097:blood*; D012015:Reference Standards; D000514:alpha 1-Antichymotrypsin / Q000097:blood
chemical_list: D000514:alpha 1-Antichymotrypsin; D017430:Prostate-Specific Antigen