ABSTRACT
Cellobiose phosphorylase from Clostridium thermocellum catalyzed the beta-anomer-selective synthesis of alkyl glucosides from cellobiose. Synthesis of alkyl beta-glucoside from inexpensive sucrose using cellobiose phosphorylase and sucrose phosphorylase from Pseudomonas saccharophilia was investigated. By combined use of these two phosphorylases, alkyl beta-glucoside was anomer-selectively synthesized from sucrose and alkyl alcohol.
Subject(s)
Glycosides/chemical synthesis , Sucrose/metabolism , Alcohols/metabolism , Glucosides/metabolism , Glucosyltransferases/metabolism , Glycosides/metabolismABSTRACT
A maltose phosphorylase (EC 2.4.1.8; MPase) showed novel acceptor specificity and transferred the glucosyl moiety of maltose not only to sugars but also to various acceptors having alcoholic OH groups. Salicyl alcohol acted as acceptor for MPase from Enterococcus hirae, and the product, salicyl-O-alpha-D-glucopyranoside (alpha-SalGlc) was identified. The yield based on supplied salicyl alcohol was 86% (mol/mol).
Subject(s)
Glucosides/chemical synthesis , Glucosyltransferases/metabolism , Benzyl Alcohols/metabolism , Enterococcus/enzymology , Glucose/metabolism , Maltose/metabolismABSTRACT
Glutathione (GSH) is synthesized by gamma-glutamylcysteine synthetase (gamma-GCS) and glutathione synthetase (GS) in living organisms. Recently, bifunctional fusion protein, termed gamma-GCS-GS catalyzing both gamma-GCS and GS reactions from gram-positive firmicutes Streptococcus agalactiae, has been reported. We revealed that in the gamma-GCS activity, S. agalactiae gamma-GCS-GS had different substrate specificities from those of Escherichia coli gamma-GCS. Furthermore, S. agalactiae gamma-GCS-GS synthesized several kinds of gamma-glutamyltripeptide, gamma-Glu-X(aa)-Gly, from free three amino acids. In Clostridium acetobutylicum, the genes encoding gamma-GCS and putative GS were found to be immediately adjacent by BLAST search, and had amino acid sequence homology with S. agalactiae gamma-GCS-GS, respectively. We confirmed that the proteins expressed from each gene showed gamma-GCS and GS activity, respectively. C. acetobutylicum GS had broad substrate specificities and synthesized several kinds of gamma-glutamyltripeptide, gamma-Glu-Cys-X(aa). Whereas the substrate specificities of gamma-GCS domain protein and GS domain protein of S. agalactiae gamma-GCS-GS were the same as those of S. agalactiae gamma-GCS-GS.