Identification of a novel α-amylase by expression of a newly cloned human amy3 cDNA in yeast

Kouichi Shiosaki, Ken ichi Takata, Kaoru Omichi, Naohiro Tomita, Akira Horii, Michio Ogawa, Kenichi Matsubara

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


A novel amylase gene (amy3) that differs in nucleotide sequence from salivary amylase gene (amyl) and pancreatic amylase gene (amy2) has been described [Tomita et al., Gene 76 (1989) 11-18], but whether this gene can ever code for an active enzyme has not been shown. We prepared cDNA of this gene from an mRNA obtained from lung carcinoid tissue, and expressed it in Saccharomyces cerevisiae under the control of an acid phosphatase promoter. The product was secreted into culture media, and showed enzymatic activity, demonstrating that this novel α-amylase gene (amy3) can code for a functional isozyme. We purified this enzyme, and compared its biological properties with those of salivary and pancreatic human amylases similarly expressed in yeast. We observed that the novel amylase isozyme is more heat-sensitive than others, and that its substrate specificity is different from the other two isozymes.

Original languageEnglish
Pages (from-to)253-258
Number of pages6
Issue number2
Publication statusPublished - 1990 May 14
Externally publishedYes


  • Recombinant DNA
  • Saccharomyces cerevisiae
  • acid phosphatase promoter
  • isozymes
  • secretion
  • substrate specificity

ASJC Scopus subject areas

  • Genetics


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