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The structural gene and the regulatory DNA sequence of the yeast Hansenula polymorpha methanol oxidase have been isolated. According to the nucleotide sequence data obtained, the structural gene encodes a 664 amino acids long protein, contains no intervening sequences, and the 5'- and 3'-non-coding region contains several sequences implicated in transcription initiation and termination in the yeast Saccharomyces cerevisiae. Although the methanol oxidase is translocated to the peroxisomes, no cleavable signal sequence was found at the N-terminus of the protein.

The biosynthesis of methanol oxidase, a peroxisomal enzyme in the methanol-utilizing yeast Hansenula polymorpha, was studied in vitro. Translation of Hansenula mRNA in a rabbit reticulocyte lysate yields methanol oxidase protein in high amounts. The apparent molecular mass of the protein was found to be identical to the subunit of the functional multimeric enzyme, which indicates the absence of an N-terminal extension typical of most transported proteins. The regulation of methanol oxidase by glucose repression and depression as well as by induction of methanol was shown to be controlled at the level of transcription. Two mutants of Hansenula polymorpha, unable to grow on methanol as a carbon and energy source were shown to be affected in methanol oxidase synthesis.

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