Problems encountered in measuring erythrocyte pyrimidine 5'-nucleotidase activity

A spectrophotometric method for the assay of pyrimidine 5'-nucleotidase in human erythrocytes

A new spectrophotometric assay for human erythrocyte pyrimidine 5'-nucleotidase using a continuous spectrophotometric method is described. The activity is detected by measuring uracil, which is produced by a coupled assay including cytidine deaminase and uridine nucleosidase. The results obtained with the continuous spectrophotometric method have been confirmed by high pressure liquid chromatography (HPLC) analysis. This procedure, not based upon inorganic phosphate formation and avoiding the use of radioactive material, offers significant advantages with respect to commonly adopted assays.

Determination of erythrocyte pyrimidine 5'-nucleotidase activity by 31P nuclear magnetic resonance: comparison of normal controls and multiple sclerosis patients

A technique to assay erythrocyte pyrimidine 5'-nucleotidase activity in situ using 31P nuclear magnetic resonance spectroscopy is presented. The assay is chemically specific, simple and applicable to untreated lysates. A comparison of enzyme levels in normal controls and in multiple sclerosis patients employing the assay yielded no significant differences between both groups. Difficulties encountered in the quantitative analysis of the assay using 1H-NMR spectroscopy are briefly discussed.

A continuous spectrophotometric assay for pyrimidine-5'-nucleotidase

A simple method is presented for the determination of pyrimidine-5'-nucleotidase activity using a continuous spectrophotometric assay system. Activity is determined by measuring inorganic phosphate generation using a linked indicator system that produces uric acid in the presence of inosine, purine nucleoside phosphorylase, and xanthine oxidase. This method has several advantages over any of the methods currently in use.