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Abstract: Glutathione (GSH) is synthesized by γ-glutamylcysteine synthetase (γ-GCS) and glutathione synthetase (GS) in living organisms. Recently, bifunctional fusion protein, termed γ-GCS–GS catalyzing both γ-GCS and GS reactions from gram-positive firmicutes Streptococcus agalactiae, has been reported. We revealed that in the γ-GCS activity, S. agalactiae γ-GCS–GS had different substrate specificities from those of Escherichia coli γ-GCS. Furthermore, S. agalactiae γ-GCS–GS synthesized several kinds of γ-glutamyltripeptide, γ-Glu-Xaa-Gly, from free three amino acids. In Clostridium acetobutylicum, the genes encoding γ-GCS and putative GS were found to be immediately adjacent by BLAST search, and had amino acid sequence homology with S. agalactiae γ-GCS–GS, respectively. We confirmed that the proteins expressed from each gene showed γ-GCS and GS activity, respectively. C. acetobutylicum GS had broad substrate specificities and synthesized several kinds of γ-glutamyltripeptide, γ-Glu-Cys-Xaa. Whereas the substrate specificities of γ-GCS domain protein and GS domain protein of S. agalactiae γ-GCS–GS were the same as those of S. agalactiae γ-GCS–GS. [Copyright &y& Elsevier]

The article discusses a maltose phosphorylase (MPase) that showed novel acceptor specificity and transferred the glucosyl moiety of maltose not only to sugars but also to various acceptors having alcoholic hydroxyl groups. Salicyl alcohol acted as acceptor for MPase from Enterococcus hirae, and the product, salicyl-O-a-D-glucopyranoside, was identified. The yield based on supplied salicyl alcohol was 86% (mol/mol).

The article focuses on the scientific concept of cellobiose phospholase from clostridium thermocellum. It catalyzes the anomer-selective synthesis of alkyl glucosides from cellobiose. Synthesis of alkyl-glucoside from inexpensive sucrose using cellobiose phosphorylase and sucrose phosphorylase from Pseudomonas saccharophilia was investigated.