Molecular cloning, sequencing, and expression of a cDNA encoding alpha-glucosidase from Mucor javanicus.

A cDNA encoding Mucor javanicus alpha-glucosidase was cloned and sequenced by the reverse transcription-polymerase chain reaction and rapid amplification of cDNA ends methods. The cDNA comprised 2,751 bp, and included an open reading frame which encodes a polypeptide of 864 amino acid residues with a molecular mass of 98,759 Da. The deduced amino acid sequence showed homology of fungal and mammalian alpha-glucosidases and related enzymes, and the sequence around the putative active site was well conserved among these enzymes. The cloned gene was expressed in Escherichia coli cells to produce the alpha-glucosidase, which hydrolyzes not only maltose, but also soluble starch.