Sapporo Breweries Limited

Naohiro Yoshigi

Yukio Okada

Hideo Maeba

Kazutoshi Ito

Makoto Kihara

Takahide Chikano

Yoshitada Mori

Tissue-specific promoter

A recombinant .beta.-amylase which is superior to the original recombinant .beta.-amylase in thermostability has been obtained by a site-directed mutagenesis with the recombinant .beta.-amylase gene coding 531 amino acid residues. Substitutions were MET.sub.181 of said enzyme with Leu, Ser.sub.291 with Ala, Ile.sub.293 with Val, Ser.sub.346 with Pro, Ser.sub.347 with Pro, Gln.sub.348, with Asp and Ala.sub.372 with Ser.

Recombinant .beta.-amylase

Barley .beta. amylase structural gene

A recombinant .beta.-amylase which is superior to the original recombinant .beta.-amylase in thermostability has been obtained by a site-directed mutagenesis with the recombinant .beta.-amylase gene coding 531 amino acid residues. Substitutions were MET.sub.181 of said enzyme with Leu, Ser.sub.291 with Ala, Ile.sub.293 with Val, Ser.sub.346 with Pro, Ser.sub.347 with Pro, Gln.sub.348 with Asp and Ala.sub.372 with Ser.

A process for the preparation of maltopentaose is disclosed, comprising cultivating a maltopentaose-producing microorganism belonging to a genus Bacillus in a medium and isolating the thus-accumulated maltopentaose from the culture broth. A typical example of the maltopentaose-producing microorganism is Bacillus cereus NY-14. This process permits the preparation of maltopentoase without the use of amylase as in conventional methods. Maltopentaose is useful, for example, as a substrate for the determination of serum amylase.

Process for the preparation of maltopentaose

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Yaizu, Japan

Naohiro Yoshigi