Characterization of prosthetic groups of naphthalene oxygenase from Corynebacterium renale
Srivastava, M.; Dua, R.D.
Indian Journal of Biochemistry and Biophysics 22(1): 13-17
1985
ISSN/ISBN: 0301-1208 PMID: 4030001 Document Number: 256571
Naphthalene oxygenase from C. renale catalyzes the oxygenation of naphthalene to give only cis-1,2-dihydroxy-1,2-dihydronaphthalene. The enzyme is sulfhydryl protein as the activity is inhibited by sulfhydryl specific reagents such as p-chloromercuribenzoate, N-ethyl maleimide and iodoacetate and this inhibition is reversed on the addition of reduced glutathione or dithiothreitol. Tryptic digestion of the enzyme reveals FAD as the coenzyme which is confirmed by atebrin inhibition and reversal of inhibition by FAD. The enzyme contains 1 mol of FAD/mol of protein. Loss of enzymic activity on preincubation with chelating agents such as o-phenanthroline, 8-hydroxyquinoline and 2,2'-dipyridyl suggested that the enzyme is a metalloprotein. The enzyme contains 1 g atom of Fe/mol of the protein. Reconstitution experiments show that the Fe of the protein is present as Fe2+ and recovery of apoenzyme activity parallels addition of Fe2+ up to 1 g atom/mol of the protein.