This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Web of Science (54) Citing Articles via Google Scholar Google Scholar Articles by Sekimata, M. Articles by Yamamoto, S. Search for Related Content PubMed PubMed Citation Articles by Sekimata, M. Articles by Yamamoto, S. Agricola Articles by Sekimata, M. Articles by Yamamoto, S.

Metabolism and Enzymology

A -Galactosidase from Radish (Raphanus sativus L.) Seeds

Department of Biochemistry, Faculty of Science, Saitama University, 255 Shimo-okubo, Urawa 338, Japan, Laboratory of Serology and Biochemistry, National Institute of Police Science, 6 Sanban-cho, Chiyoda-ku, Tokyo 102, Japan

A basic -galactosidase (-Galase) has been purified 281-fold from imbibed radish (Raphanus sativus L.) seeds by conventional purification procedures. The purified enzyme is an electrophoretically homogeneous protein consisting of a single polypeptide with an apparent molecular mass of 45 kilodaltons and pl values of 8.6 to 8.8. The enzyme was maximally active at pH 4.0 on p-nitrophenyl -D-galactoside and -1,3-linked galactobiose. The enzyme activity was inhibited strongly by Hg²⁺ and 4-chloromercuribenzoate. D-Galactono-(14)-lactone and D-galactal acted as potent competitive inhibitors. Using galactooligosaccharides differing in the types of linkage as the substrates, it was demonstrated that radish seed -Galase specifically split off -1,3- and -1,6-linked D-galactosyl residues from the nonreducing ends, and their rates of hydrolysis increased with increasing chain lengths. Radish seed and leaf arabino-3,6-galactan-proteins were resistant to the -galase alone but could be partially degraded by the enzyme after the treatment with a fungal -L-arabinofuranosidase leaving some oligosaccharides consisting of D-galactose, uronic acid, L-arabinose, and other minor sugar components besides D-galactose as the main product.

This article has been cited by other articles:

				T. Sakamoto, Y. Taniguchi, S. Suzuki, H. Ihara, and H. Kawasaki Characterization of Fusarium oxysporum {beta}-1,6-Galactanase, an Enzyme That Hydrolyzes Larch Wood Arabinogalactan Appl. Envir. Microbiol., May 1, 2007; 73(9): 3109 - 3112. [Abstract] [Full Text] [PDF]

				T. Kotake, K. Tsuchiya, T. Aohara, T. Konishi, S. Kaneko, K. Igarashi, M. Samejima, and Y. Tsumuraya An {alpha}-L-arabinofuranosidase/{beta}-D-xylosidase from immature seeds of radish (Raphanus sativus L.) J. Exp. Bot., July 1, 2006; 57(10): 2353 - 2362. [Abstract] [Full Text] [PDF]

				T. Kotake, S. Dina, T. Konishi, S. Kaneko, K. Igarashi, M. Samejima, Y. Watanabe, K. Kimura, and Y. Tsumuraya Molecular Cloning of a {beta}-Galactosidase from Radish That Specifically Hydrolyzes {beta}-(1->3)- and {beta}-(1->6)-Galactosyl Residues of Arabinogalactan Protein Plant Physiology, July 1, 2005; 138(3): 1563 - 1576. [Abstract] [Full Text] [PDF]

				A. Tateishi, H. Inoue, H. Shiba, and S. Yamaki Molecular Cloning of {beta}-Galactosidase from Japanese Pear (Pyrus pyrifolia) and its Gene Expression with Fruit Ripening Plant Cell Physiol., May 1, 2001; 42(5): 492 - 498. [Abstract] [Full Text] [PDF]

				A. T. Carey, D. L. Smith, E. Harrison, C. R. Bird, K. C. Gross, G. B. Seymour, and G. A. Tucker Down-regulation of a ripening-related {beta}-galactosidase gene (TBG1) in transgenic tomato fruits J. Exp. Bot., April 15, 2001; 52(357): 663 - 668. [Abstract] [Full Text] [PDF]