Purification of Human Myeloperoxidase by Concanavalin A-Sepharose Affinity Chromatography

Myeloperoxidase (E.C. 1.11.1.7. Donor: H2O2 oxidoreductase), an enzyme of the azurophil granule of polymorphonuclear leukocytes, has been purified from the blood of a single human donor. Leukocytes were harvested by dextran sedimentation and contaminating erythrocytes were removed by hypotonic lysis. Myeloperoxidase was extracted from the leukocytes by dissolution in cetyltrimethyl-ammonium bromide (CETAB). The extract was adsorbed to a Con A-Sepharose gel, eluted with alpha-methyl-D-mannoside and rechromatographed on Sephadex G-200. Approximately 100% of the initial peroxidase activity was recovered in the final preparation, which was homogeneous by polyacrylamide disc gel electrophoresis at pH 4.5 and displayed the typical oxidized and reduced absorption spectra of purified myeloperoxidase. The oxidized enzyme showed a Soret maximum at 430 nm which shifted to 470 nm upon reduction. The molecular weight was estimated by G-200 Sephadex gel filtration chromatography to be 146,000 daltons.