alpha-galactosidase from cultured rice (Oryza sativa L. var. Nipponbare) cells

作者：Kim WD; Kobayashi O; Kaneko S; Sakakibara Y; Park GG; Kusakabe I; Tanaka H; Kobayashi H^*

来源：Phytochemistry, 2002, 61(6): 621-630.

DOI：10.1016/S0031-9422(02)00368-0

• alpha-galactosidase
• galactomanno-oligosaccharides
• rice
• Oryza sativa L. var. Nipponbare
• grammimeae
• substrate specificity

The alpha-galactosidase from rice cell suspension cultures was purified to homogeneity by different techniques including affinity chromatography using N-epsilon-aminocaproyl-alpha-D-galactopyranosylamine as the ligand. From 111 of culture filtrate, 28.7 mg of purified enzyme was obtained with an overall yield of 51.9%. The cDNA coding for the alpha-galactosidase was cloned and sequenced. The enzyme was found to contain 417 amino acid residues composed of a 55 amino acid signal sequence and 362 amino acid mature alpha-galactosidase; the molecular weight of the mature enzyme was thus calculated to be 39,950. Seven cysteine residues were also found but no putative N-glycosylation sites were present. The observed homology between the deduced amino acid sequences of the mature enzyme and alpha-galactosidases from coffee (Coffea arabica), guar (Cyamopsis tetragonolooba), and Mortierella vinacea alpha-galactosidase II were over 73, 72, and 45%, respectively. The enzyme displayed maximum activity at 45 degreesC when p-nitrophenyl-alpha-D-galactopyranoside was used as substrate. The rice alpha-galactosidase and Mortierella vinacea alpha-galactosidase II acted on both the terminal alpha-galactosyl residue and the side-chain alpha-galactosyl residue of the galactomanno-oligosaccharides.

• 出版日期2002-11