PHOSPHOROLYTIC SYNTHESIS OF CELLODEXTRINS

摘要

Transglucosylation reactions catalyzed by cellodextrin phosphorylase from Clostridium thermocellum were reinvestigated by using a series of cellobiosyl residues as glycosyl accepters and alpha-D-glucopyranosyl phosphate (Glc-1-P) as glycosyl donor. When cellobiose was used as an acceptor, various unsubstituted cellodextrins, ranging from water-soluble products to crystalline precipitates were obtained, depending on the concentration in acceptor. 4-Thiocellobiose, methyl beta-cellobioside, and methyl 4-thio-alpha-cellobioside could also be used as accepters with the same efficiency as cellobiose. The enzyme showed higher activity when beta-cellobiosides bearing strong hydrophobic aglycons were used. A practical preparation of methyl beta-cellotrioside, cellotetraoside and cellopentaoside was achieved, using a 1:5 molar ratio of methyl beta-cellobioside to the glucosyl donor. [References: 32]