Distribution of selenium and glutathione peroxidase in plasma compared in healthy subjects and rheumatoid arthritis patients.

Abstract

The distribution of selenium and glutathione peroxidase activity in plasma was compared in samples from healthy adult controls and patients with rheumatoid arthritis. Plasma was separated by gel filtration, and selenium was measured in the eluted fractions by means of graphite furnace atomic absorption spectrometry with Zeeman background correction. Most of the selenium in plasma of healthy controls was seen in proteins that migrated close to immunoglobulin G, and that had an apparent molecular weight at the peak of 174 kDa. One major peak of glutathione peroxidase activity with an apparent molecular weight of 99 kDa was unmatched by any significant peak in selenium content. Thus, there was only limited correspondence between the elution patterns of selenium and glutathione peroxidase activity. Also, in patients with active rheumatoid arthritis, selenium was distributed amongst plasma proteins with a wide range of molecular weights. The major selenium peak was less pronounced in patients, but the amount of selenium in other parts of the chromatogram was not different from that in controls. Further work is necessary to define the occurrence of different selenoproteins in plasma in patients and in healthy subjects.