Pseudo-inhibitors of neutrophil superoxide production: evidence that soybean-derived polypeptides are superoxide dismutases.
We have previously reported the purification of polypeptides from soybean which are potent inhibitors of superoxide production by human neutrophils. We now report that neither oxygen uptake nor hydrogen peroxide production by stimulated neutrophils is affected by these inhibitors. Furthermore, the E-1 and E-3 polypeptides inhibit ferricytochrome c reduction by a xanthine oxidase superoxide generation system. The inhibitory activity of E-3 in the model system is blocked by 1 mM KCN while E-1 is only slightly cyanide sensitive. Atomic absorption analysis of E-1 and E-3 polypeptides reveal copper in the latter and manganese in the former. Thus, E-3 is a copper-containing superoxide dismutase while E-1 appears to be a manganese-containing superoxide dismutase.
D003300:Copper / Q000032:analysis; D006801:Humans; D007700:Kinetics; D008345:Manganese / Q000032:analysis; D008970:Molecular Weight; D009504:Neutrophils / Q000378:metabolism*; D010940:Plant Proteins / Q000302:isolation & purification / Q000378:metabolism*; D013025:Glycine max; D013482:Superoxide Dismutase / Q000302:isolation & purification / Q000378:metabolism*; D013481:Superoxides / Q000097:blood*
D010940:Plant Proteins; D013481:Superoxides; D008345:Manganese; D003300:Copper; D013482:Superoxide Dismutase