| Abstract: | Phosphorolysis of α,α-trehalose catalyzed by trehalose phosphorylase from the basidiomycete Schizophyllum commune proceeds via net retention of anomeric configuration and yields α--glucose 1-phosphate and α--glucose as the products. In reverse reaction, only the α-anomers of -glucose 1-phosphate and -glucose are utilized as glucosyl donor and acceptor, respectively, and give exclusively the α,α-product. Trehalose phosphorylase converts α--glucose 1-fluoride and phosphate into α--glucose 1-phosphate, a reaction requiring the stereospecific protonation of the glucosyl fluoride by a Brønsted acid. The results are discussed with regard to a plausible reaction mechanism of fungal trehalose phosphorylase. |
