Synthesis of oligosaccharides using glycosidase enzymes indigeneous to Thailand
1995
Chitsanu Sawatdiwat | Surarit, R. | Benjavongkulchai, E. | Chantharakan Phiphopmongkhon | Bucke, Christopher (Mahidol Univ., Bangkok (Thailand). Faculty of Science. Dept. of Biochemistry)
Study the synthesis of oligosaccharides by screening the seeds of more than 50 species of Thai plants from 17 families for nine glycosidase enzymes. The enzymes Alpha-D-mannosidase, Beta-D-glucosidase, Beta-D-fucosidase, Alpha-D-galactosidase, Beta-D-galactosidase and Beta-D-N-acetyl-glucosaminidase were found. A glycosidase enzyme with both Beta-glucosidase and Beta-fucosidase activities was purified from the seeds of Dalbergia cochinchinensis Pierre (Thai Rosewood) by ammonium sulfate fractionation, preparative isoelectric focusing and Sephadex G-150 chromatography. Beta-Galactosidase was purified from the seeds of Thai jute (Hibiscus sabdariffa L. var. altissima) by ammonium sulfate fractionation, DEAE-cellulose column chromatography, Sephadex G-100 column chromatography, Lactosyl-Sepharose chromatography, and a second DEAE-cellulose chromatography step. Alpha-D-mannosidases were partially purified from Albizzia procera Benth, Hibiscus sabdariffa var. sabdariffa, Hibiscus sabdariffa var. altissima, and Vigna umbellata using various column chromatographic techniques. Synthesis by Beta-glucosidase from Hibiscus sabdariffa var altissima incubated with D-galactose showed rather low maximal yields of 15 percent. Optimum pH was 3-4, but temperatures from 40-80 deg C showed little difference, and 20-30 percent galactose appeared to be optimal. In conclusion, synthesis studies carried out with all these enzymes showed that maximal synthesis depended on enzyme and varied from 5 percent up to 35-40 percent.
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