Causes of the production of multiple forms of β-galactosidase by Bacillus circulans

Jingyuan Song, Kiriko Abe, Hiroyuki Imanaka, Koreyoshi Imamura, Masashi Minoda, Shotaro Yamaguchi, Kazuhiro Nakanishi

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37 Citations (Scopus)


The presence of multiple types of β-galactosidases in a commercial enzyme preparation from Bacillus circulans ATCC 31382 and differences in their trans-galactosylation activity were investigated. Four β-gal-actosidases, β-Gal-A, β-Gal-B, β-Gal-C, and β-Gal-D, which were immunologically homologous, were isolated and characterized. The N-terminal amino acid sequences of all of the enzymes were identical and biochemical characteristics were similar, except for galactooligosaccharide production. β-Gal-B, β-Gal-C, and jS-Gal-D produced mainly tri- and tetra saccharides at maximum yields of 20-30 and 9-12%, while β-Gal-A produced trisaccharide with 7% with 5% lactose as substrate. The Lineweaver-Burk plots for all of the enzymes, except for β-Gal-A, showed biphasic behavior. β-Gal-A was truncated to yield multiple β-galactosidases by treatment with protease isolated from the culture broth of B. circulans. Treatment of β-Gal-A with trypsin yielded an active 91-kDa protein composed of 21-kDa and 70-kDa proteins with characteristics similar to those for β-Gal-D.

Original languageEnglish
Pages (from-to)268-278
Number of pages11
JournalBioscience, Biotechnology and Biochemistry
Issue number2
Publication statusPublished - 2011


  • Bacillus circulans
  • Galactooligosaccharide
  • Trans-galactosylation
  • β-galactosidase

ASJC Scopus subject areas

  • Biotechnology
  • Analytical Chemistry
  • Biochemistry
  • Applied Microbiology and Biotechnology
  • Molecular Biology
  • Organic Chemistry


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