Purification and characterization of a novel glycosidase from the china white jade snail (Achatinafulica) showing transglycosylation activity

摘要

A broad specificity β-D-glycosidase, designated G I, was purified to homogeneity from the viscera of the China white jade snail (Achatina fulica). The enzyme was a monomelic protein with molecular weight of 115 kDa. G I has broad glycone specificity towards p-nitrophenyl derivatives of β-D-glucose, β-D-fucose, β-D-galactose, α-D-glucose and some disaccharides. The optimum pH and temperature are 5.5 and 55 °C, respectively. It was stable over a wide pH range (5-10 at 30 °C for 24 h) and against a relatively high temperature (50 °C for 4h). Moreover, it was also stable and active in the presence of various alcohols. With pNPGlu, pNPFuc and cellobiose as donor, G I showed high transglycosylation activity. Six transglycosylation products were isolated from the reaction mixture containing 20% alcohol as glycoside acceptor using a preparative thin layer chromatography (preparative TLC) and identified as alkyl-glucosides and alkyl-fucosides by mass spectrometry (MS) analysis. Combining the high alcohol tolerance, moderate temperature and pH stability and alkyl glycosides production efficiency through transglycosylation, G I can be considered to be a promising candidate for the production of various alkyl glycosides.