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.