Purification of cytochrome P-450alk from n-alkane-grown cells of Candida maltosa, and cloning and nucleotide sequencing of the encoding gene.

Abstract

When the cells of an n-alkane-assimilating yeast, Candida maltosa I AM 12247, were transferred from a glucose medium to an n-alkane medium, various enzymes are induced in the endoplasmic reticulum and peroxisome. Cytochrome P-450alk, one of these enzymes in the endoplasmic reticulum, was purified after mild solubilization of the membrane, followed by a few steps of chromatography. The enzyme was characterized spectrophotometrically and its N-terminal amino acid sequence (12 residues) was determined. Using oligonucleotide probes prepared to match parts of the N-terminal amino acid sequence and 4 of the partial cDNA sequence of Cytochrome P-450alk of C. maltosa EH 15, we isolated from a gene library of C. maltosa I AM 12247 a clone which had a gene encoding Cytochrome P-450alk. By nucleotide sequencing of this gene, the amino acid sequence of this enzyme was deduced. It consisted of 523 amino acids (59, 838 daltons), with a non-cleavable signal sequence in the N-terminal region. The structure of this enzyme was compared with some other members of the cytochrome P-450 superfamily.