Isolation and identification of three water-soluble selenoproteins in Se-enriched Agaricus blazei Murrill

Selenopmteins in selenium (Se)-enriched vegetables play an important role in human health. In this study, three water-soluble selenoproteins PR-Se-1, PR-Se-2 and PR-Se-3 in Agaricus blazei Murrill (ABM) were isolated by anion exchange chromatography, gel filtration chromatography and SDS-PAGE. Sequence analyses performed by HPLC-MS/MS showed that PR-Se-1, a 114024 Da selenoprotein with 1019 amino acids (AAs), is an isoenzyme of isocitrate dehydrogenase. PR-Se-2, a 53983 Da selenoprotein with 508 AAs, is a kind of dihydrolipoyl dehydrogenase. PR-Se-3, a 47179 Da selenopmtein with 415 AAs, is a kind n-proline reductase. Se content is high at 26.1 mu g/g, and selenocystine is the predominant Se unit in the three selenoproteins. Se content of ABM is 9.15 mu g/g, and the organic form of Se accounts for similar to 81% of total Se content. ABM could be a promising source of Se in Se-poor regions.

Automated summary

Selenoproteins PR-Se-1, PR-Se-2, and PR-Se-3 were isolated from Agaricus blazei Murrill (ABM) and identified as isoenzymes of isocitrate dehydrogenase, dihydrolipoyl dehydrogenase, and n-proline reductase, respectively. ABM is a promising source of selenium in selenium-poor regions, with organic selenium comprising about 81% of its total selenium content.