[Metlegoglobin reductase from lupine nodules. Purification and properties].

The purification procedure and properties of metlegoglobin reductase from the soluble fraction of lupine (Lupinus luteus L.) nodules and from the proteins secreted by bacteroids Rhizobium lupini in vitro are described. The properties of both forms of enzyme were found to be similar. A metlegoglobin reductase preparation purified 125-fold with a yield of 21% was obtained. The enzyme is strictly specific to the cofactor (NADH). No substrate specificity was revealed. The enzyme reduces oxidized cytochrome c, Mb+, Lb+, Hb+ and exygen. The pH optimum for the enzyme is 7,4. The enzyme is inhibited by p-chloromercurybenzoate. In some properties the enzyme from lupine nodules is close to methemoglobin reductase from the erythrocytes. It was shown that apart from metlegoglobin reductase, bacteroids secrete some other proteins, which is indicative of a close interrelationship between the bacteroids and the plant in a symbiotic nitrogen-fixing system.