title: Enzymatic activity and substrate specificity of the recombinant tomato β-galactosidase 1.
abstract: The open reading frame of tomato β-galactosidase 1 was expressed in yeast, and the enzymatic properties and substrate specificity were investigated. The enzyme had peak activity at pH 5.0 and 40-50°C. TBG1 was active on β-(1,3)- and β-(1,6)-galactobiose and lactose. TBG1 released galactose from lupin galactan, tomato fruit alkali soluble pectin, arabinogalactan, gum arabic and methyl β-(1,6)-galactohexaoside, but not from labeled β-(1,4)-galactoheptaose. TBG1 was assessed for its ability to degrade three galactosyl-containing cell wall fractions purified from different development and ripening stages of tomato fruit. TBG1 released galactose from all of the fractions from all of the stages tested. TBG1 activity was highest on the hemicellulose fraction at the 10 and 20d after pollination stage. This result is not correlated the with TBG1 expression pattern. TBG1 might act on a small but specific set of polysaccharide containing galactose.
authors.affiliation: Graduate School of Science, Osaka Prefecture University, Gakuen-cho, Sakai, Osaka 599-8531, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Eda
authors.affiliation: Faculty of Biology-Oriented Science and Technology, Kinki University, Nishimitani, Kinokawa, Wakayama 649-6493, Japan. Electronic address: ishimaru@waka.kindai.ac.jp.
authors.forename: Megumi
authors.initials: M
authors.lastname: Ishimaru
authors.affiliation: Graduate School of Science, Osaka Prefecture University, Gakuen-cho, Sakai, Osaka 599-8531, Japan.
authors.forename: Toshiji
authors.initials: T
authors.lastname: Tada
authors.affiliation: Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Gakuen-cho, Sakai, Osaka 599-8531, Japan.
authors.forename: Tatsuji
authors.initials: T
authors.lastname: Sakamoto
authors.affiliation: Graduate School of Science and Engineering, Saitama University, Shimo-okubo, Sakura-ku, Saitama 338-8570, Japan.
authors.forename: Toshihisa
authors.initials: T
authors.lastname: Kotake
authors.affiliation: Graduate School of Science and Engineering, Saitama University, Shimo-okubo, Sakura-ku, Saitama 338-8570, Japan.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Tsumuraya
authors.affiliation: Department of Biochemistry and Molecular Biology, Oklahoma State University, 246 Noble Research Center, Oklahoma State University, Stillwater, OK 74078-3035, USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Mort
authors.affiliation: Produce Quality and Safety Laboratory, USDA-ARS, Building 002, Henry A. Wallace Beltsville Area Research Center, 10300 Baltimore Avenue, Beltsville, MD 20705-2350, USA.
authors.forename: Kenneth C
authors.initials: KC
authors.lastname: Gross
mesh_terms: D005638:Fruit / Q000378:metabolism; D005690:Galactose / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D013379:Substrate Specificity; D001616:beta-Galactosidase / Q000235:genetics* / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D011994:Recombinant Proteins; D001616:beta-Galactosidase; D005690:Galactose
keywords: Cell wall; Exo-galactanase; Solanum lycopersicum; Substrate specificity; β-Galactosidase