Cloning and nucleotide sequence of the maltopentaose-forming amylase gene from Pseudomonas sp. KO-8940.

The gene coding for the maltopentaose-(G5)-forming amylase of Pseudomonas sp. KO-8940 was cloned into Escherichia coli and its nucleotides were sequenced. It was expected that a long open reading frame composed of 1,842-bp that encoded 614 amino acid residues for secretory precursor polypeptide including the typical signal sequence with an NH2-terminal was the gene. An extract of Escherichia coli carrying the cloned G5-forming amylase gene had amylolytic activity with which produced only G5 from starch, the same as that of the donor strain enzyme. In the deduced primary structure of this enzyme, the four conserved regions of many alpha-amylases were found, and the COOH-terminal portion of this enzyme showed high homology with other raw starch digesting amylases.