Purification and characterization of two phospho-β-galactosidases, LacG1 and LacG2, from lactobacillus gasseri ATCC33323 T

Hiroyuki Honda, Seiji Nagaoka, Yasushi Kawai, Robèr Kemperman, Jan Kok, Yukiko Yamazaki, Yoshio Tateno, Haruki Kitazawa, Tadao Saito

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    9 Citations (Scopus)

    Abstract

    Lactobacillus gasseri ATCC33323 T expresses four enzymes showing phospho-β-galactosidase activity (LacG1, LacG2, Pbg1 and Pbg2). We previously reported the purification and characterization of two phospho-β-galactosidases (Pbg1 and Pbg2) from Lactobacillus gasseri JCM1031 cultured in lactose medium. Here we aimed to characterize LacG1 and LacG2, and classify the four enzymes into 'phospho-β-galactosidase' or 'phospho-β-glucosidase.' LacG1 and recombinant LacG2 (rLacG2), from Lb. gasseri ATCC33323 T, were purified to homogeneity using column chromatography. Kinetic experiments were performed using sugar substrates, o-nitrophenyl-β- D-galactopyranoside 6-phosphate (ONPGal-6P) and o-nitrophenyl-β-D-glucopyranoside 6-phosphate (ONPGlc-6P), synthesized in our laboratory. LacG1 and rLacG2 exhibited high k cat/K m values for ONPGal-6P as compared with Pbg1 and Pbg2. The Vmax values for ONPGal-6P were higher than phospho-β-galactosidases previously purified and characterized from several lactic acid bacteria. A phylogenetic tree analysis showed that LacG1 and LacG2 belong to the phospho-β-galactosidase cluster and Pbg1 and Pbg2 belong to the phospho-β-glucosidase cluster. Our data suggest two phospho-β-galactosidase, LacG1 and LacG2, are the primary enzymes for lactose utilization in Lb. gasseri ATCC33323 T. We propose a reclassification of Pbg1 and Pbg2 as phospho-β-glucosidase.

    Original languageEnglish
    Pages (from-to)11-17
    Number of pages7
    JournalJournal of General and Applied Microbiology
    Volume58
    Issue number1
    DOIs
    Publication statusPublished - 2012

    Keywords

    • Lactic acid bacteria
    • Lactobacillus gasseri
    • Lactose utilization
    • Phospho-β-galactosidase
    • Phospho-β-glucosidase

    ASJC Scopus subject areas

    • Microbiology
    • Applied Microbiology and Biotechnology

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