THE OXIDASE ACTIVITY OF SERUM CERULOPLASMIN IN MULTIPLE SCLEROSIS

Abstract We have developed a new method for determination of serum ceruloplasmin from its oxidase activity, in which o-dianisidine dihydrochloride is used as substrate. o-Dianisidine dihydrochloride is more stable than is the more widely used p-phenylenediamine substrate, and forms a stable product that is measured at 540 nm. Correlation was good between results of this method and those obtained with both a p-phenylenediamine substrate method (r = 0.98) and a radial immunodiffusion procedure (r = 0.97). There is little or no interference from reducing or colored components of serum. The coefficient of variation (day-to-day) for the method was 4.2%. A normal range of 62-140 U/ liter has been determined by the reported method.

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Standardization of Serum Ceruloplasmin Concentrations in International Enzyme Units with o-Dianisidine Dihydrochloride as Substrate

Clinical Chemistry ◽

10.1093/clinchem/20.12.1564 ◽

1974 ◽

Vol 20 (12) ◽

pp. 1564-1567 ◽

Cited By ~ 65

Author(s):

H Peter Lehmann ◽

Karl H Schosinsky ◽

Myrton F Beeler

Keyword(s):

Hydrogen Peroxide ◽

Oxidase Activity ◽

Serum Ceruloplasmin

Abstract We describe a method for calculating the absorptivity (in terms of substrate consumed) of the colored solution obtained when o-dianisidine dihydrochloride is oxidized by ceruloplasmin. By oxidizing o-dianisidine dihydrochloride with known amounts of hydrogen peroxide we could determine that the molar reacting ratio of o-dianisidine to hydrogen peroxide is 2:1. So calculated, absorptivity is 9.6 ml µmol-1 cm-1, the figure used to estimate ceruloplasmin oxidase activity in terms of International Units.

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Truncating mutations in the Wilson disease gene ATP7B are associated with very low serum ceruloplasmin oxidase activity and an early onset of Wilson disease

BMC Gastroenterology ◽

10.1186/1471-230x-10-8 ◽

2010 ◽

Vol 10 (1) ◽

Cited By ~ 56

Author(s):

Uta Merle ◽

Karl Heinz Weiss ◽

Christoph Eisenbach ◽

Sabine Tuma ◽

Peter Ferenci ◽

...

Keyword(s):

Wilson Disease ◽

Early Onset ◽

Oxidase Activity ◽

Disease Gene ◽

Serum Ceruloplasmin ◽

Low Serum

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

Clinical Chemistry ◽

10.1093/clinchem/16.11.903 ◽

1970 ◽

Vol 16 (11) ◽

pp. 903-910 ◽

Cited By ~ 269

Author(s):

F William Sunderman ◽

Shozo Nomoto

Keyword(s):

Oxidase Activity ◽

Chloride Concentration ◽

Reaction Conditions ◽

Serum Dilution ◽

Serum Ceruloplasmin ◽

Coefficients Of Variation ◽

Optimum Reaction ◽

The Mean ◽

Human Ceruloplasmin ◽

Improved Technique

Abstract 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).

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