PERIPLASMIC SULFIDE DEHYDROGENASE (SUD) FROM WOLINELLA-SUCCINOGENES -ISOLATION, NUCLEOTIDE-SEQUENCE OF THE SUD GENE AND ITS EXPRESSION IN ESCHERICHIA-COLI

Wolinella succinogenes contains a periplasmic sulphide dehydrogenase w hen grown with formate and polysulphide as catabolic substrates. The i solated enzyme catalyzes the reduction of dimethylnaphthoquinone with sulphide at high values of both apparent K-m and turnover number. The active enzyme consists of two identical subunits (14 kDa) and amounts to approximately 1% of the soluble cell protein. Prosthetic groups suc h as flavin, haem or molybdenum are missing. The corresponding gene (s ud) encodes a signal peptide together with the mature subunit that con sists of 129 amino acid residues including one single cysteine. The su d gene is expressed from a plasmid in Escherichia coli. The resulting enzyme catalyzes sulphide oxidation with dimethylnaphthoquinone and is located in the periplasm of E. coli.