PURIFICATION OF NADH - HYPOTHIOCYANITE OXIDOREDUCTASE IN STREPTOCOCCUS-SANGUIS

NADH: hypothiocyanite oxidoreductase (NHOR) activity, found in some or al Streptococci, is postulated to protect these microorganisms against salivary peroxidase-produced hypothiocyanite, NHOR, however, has not been purified so far. The purification of NHOR from crude extracts of Streptococcus sanguis NCTC 7863 strain (by ultrafiltation and anion-ex change chromatography) revealed one fraction of 125 +/- 1 kDa. However , SDS-PAGE electrophoresis provided a single protein of 21.1 +/- 1.2 k Da, This last discovery suggests that NHOR enzyme is a hexameric compl ex having six subunits. (C) 1996 Academic Press, Inc.