Intact form of myeloperoxidase from normal human neutrophils |
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Authors: | M R Andersen C L Atkin H J Eyre |
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Affiliation: | Hematology-Oncology Division, Department of Internal Medicine, and Department of Biological Chemistry, University of Utah School of Medicine, Salt Lake City, Utah 84132 USA |
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Abstract: | Myeloperoxidase (donor: H2O2 oxidoreductase, EC 1.11.1.7) of human polymorphonuclear neutrophils was purified rapidly in the presence of the protease inhibitors phenylmethanesulfonyl fluoride and pepstatin A. The purified enzyme behaved as a single molecular species in several nondenaturing electrophoretic and chromatographic systems. Peroxidase activity in fresh extracts of neutrophils from 20 normal persons and from 5 patients with polycythemia was electrophoretically identical to purified enzyme. Treatment with trypsin converted myeloperoxidase to multiple electrophoretic forms of active enzyme. Size (Mr ca. 15,000 and ca. 55,000) and stoichiometry of the subunits of purified enzyme, and enzyme Mr ca. 140,000, were compatible with intact myeloperoxidase having an α2β2 structure. We found no evidence for electrophoretically detectable genetic polymorphism of myeloperoxidase. Proteolytic degradation of myeloperoxidase probably accounted for electrophoretic heterogeneity of enzyme and for some constituent peptides described previously. |
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Keywords: | Address correspondence and reprint requests to Dr. Atkin. |
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