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Hokkaido University Collection of Scholarly and Academic Papers >
Graduate School of Agriculture / Faculty of Agriculture >
Peer-reviewed Journal Articles, etc >
Metabolic Mechanism of Mannan in a Ruminal Bacterium, Ruminococcus albus, Involving Two Mannoside Phosphorylases and Cellobiose 2-Epimerase : Discovery of a New Carbohydrate Phosphorylase, β-1,4-Mannooligosaccharide Phosphorylase
| Title: | Metabolic Mechanism of Mannan in a Ruminal Bacterium, Ruminococcus albus, Involving Two Mannoside Phosphorylases and Cellobiose 2-Epimerase : Discovery of a New Carbohydrate Phosphorylase, β-1,4-Mannooligosaccharide Phosphorylase |
| Authors: | Kawahara, Ryosuke Browse this author | | Saburi, Wataru Browse this author →KAKEN DB | | Odaka, Rei Browse this author | | Taguchi, Hidenori Browse this author | | Ito, Shigeaki Browse this author | | Mori, Haruhide Browse this author →KAKEN DB | | Matsui, Hirokazu Browse this author →KAKEN DB |
| Keywords: | Carbohydrate Metabolism | | Enzyme Kinetics | | Enzyme Purification | | Glycoside Hydrolases | | Phosphorylase | | Ruminococcus albus | | Glycoside Hydrolase Family 130 | | Mannan | | Mannooligosaccharide Phosphorylase | | Phosphorolysis |
| Issue Date: | 7-Dec-2012 |
| Publisher: | American Society for Biochemistry and Molecular Biology |
| Journal Title: | Journal of Biological Chemistry |
| Volume: | 287 |
| Issue: | 50 |
| Start Page: | 42389 |
| End Page: | 42399 |
| Publisher DOI: | 10.1074/jbc.M112.390336 |
| Abstract: | Ruminococcus albus is a typical ruminal bacterium digesting cellulose and hemicellulose. Cellobiose 2-epimerase (EC 5.1.3.11, CE), which converts cellobiose to 4-O-β-D-glucosyl-D-mannose, is a particularly unique enzyme in R. albus, but its physiological function is unclear. Recently, a new metabolic pathway of mannan involving CE was postulated for another CE producing bacterium, Bacteroides fragilis. In this pathway, β-1,4-mannobiose is epimerized to 4-O-β-D-mannosyl-D-glucose (Man-Glc) by CE, and Man-Glc is phosphorolyzed to α-D-mannosyl 1-phosphate (Man1P) and D-glucose by Man-Glc phosphorylase (EC 2.4.1.281, MP). Ruminococcus albus NE1 showed intracellular MP activity, and two MP isozymes, RaMP1 and RaMP2, were obtained from the cell-free extract. These enzymes were highly specific for the mannosyl residue at the non-reducing end of the substrate and catalyzed the phosphorolysis and synthesis of Man-Glc through a sequential bi bi mechanism. In a synthetic reaction, RaMP1 showed high activity only towards D-glucose and 6-deoxy-D-glucose in the presence of Man1P, while RaMP2 showed acceptor specificity significantly different from RaMP1. RaMP2 acted on D-glucose derivatives at the C2- and C3-positions including deoxy- and deoxyfluoro-analogues and epimers, but not on those substituted at the C6-position. Furthermore, RaMP2 had high synthetic activity toward the following oligosaccharides: β-linked glucobioses, maltose, N, N'-diacetylchitobiose, and β-1,4-mannooligosaccharides. Particularly, β-1,4-mannooligosaccharides served as significantly better acceptor substrates for RaMP2 than D-glucose. In the phosphorolytic reactions, RaMP2 had weak activity towards β-1,4-mannobiose but efficiently degraded β-1,4-mannooligosaccharides longer than β-1,4-mannobiose. Consequently, RaMP2 is thought to catalyze the phosphorolysis of β-1,4-mannooligosaccharides longer than β-1,4-mannobiose to produce Man1P and β-1,4-mannobiose. |
| Rights: | This research was originally published in Journal of Biological Chemistry. Ryosuke Kawahara, Wataru Saburi, Rei Odaka, Hidenori Taguchi, Shigeaki Ito, Haruhide Mori and Hirokazu Matsui. Metabolic Mechanism of Mannan in a Ruminal Bacterium, Ruminococcus albus, Involving Two Mannoside Phosphorylases and Cellobiose 2-Epimerase : Discovery of a New Carbohydrate Phosphorylase, β-1,4-Mannooligosaccharide Phosphorylase. Journal of Biological Chemistry. 2012; Vol:42389-42399. © the American Society for Biochemistry and Molecular Biology. |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/51063 |
| Appears in Collections: | 農学院・農学研究院 (Graduate School of Agriculture / Faculty of Agriculture) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 佐分利 亘
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