Measurement of Human Serum Ceruloplasmin by Its p-Phenylenediamine Oxidase Activity

[摘要] Optimum reaction conditions were evaluated for assay of serum ceruloplasmin by measurement of its p -phenylenediamine oxidase activity. The pH optima of p -phenylenediamine oxidase activities of human and rat ceruloplasmins were 5.45 and 5.2, respectively. The p -phenylenediamine oxidase activity of rat ceruloplasmin was markedly inhibited by phosphate (0.1 mol/liter), that of human ceruloplasmin only slightly. These reaction conditions were judged to be optimum for the ceruloplasmin assay: ( a ) substrate: p -phenylenediamine dihydrochloride, 8.9 mmol/liter; ( b ) buffer: acetate, 0.1 mol/liter; ( c ) chloride concentration: 21 mmol/liter; ( d ) serum dilution: 31-fold; ( e ) incubation: 37°C for 30 min; ( f ) spectrophotometry: 530 nm ( vs. a "serum blank" containing NaN3). Using these reaction conditions, we devised an improved technique for measuring serum ceruloplasmin. The coefficients of variation of replicate analyses by this technique were 1.25% (for "within-run" precision) and 2.8% (for "day-to-day" precision). The mean concentration of ceruloplasmin in sera from 29 healthy men was 0.315 g/liter (SD = ± 0.049, range = 0.233 to 0.402).

[学科分类] 过敏症与临床免疫学