γ-Glutamyltransferases (γ-GTs) are heterodimeric enzymes that catalyze the transfer of a γ-glutamyl group from a donor species to an acceptor mol. in a transpeptidation reaction through the formation of an intermediate γ-glutamyl enzyme. In the search for a γ-GT from a generally recognized as safe microorganism suitable for the prodn. of γ-glutamyl derivs. with flavor-enhancing properties intended for human use, the authors cloned and overexpressed γ-GT from Bacillus subtilis. Here, the authors report the behavior of B. subtilis γ-GT in reactions involving glutamine as the donor compd. and various acceptor amino acids. The common thread emerging from these results is a strong dependence of the hydrolase, transpeptidase, and autotranspeptidase activities of B. subtilis γ-GT on pH, also in relation to the pKa of the acceptor amino acids. Glutamine, commonly referred to as a poor acceptor mol., underwent rapid autotranspeptidation at elevated pH, affording oligomeric species, in which up to 4 γ-glutamyl moieties were linked to a single glutamine. Moreover, it was found that L-glutamine was also recognized both as a donor and as an acceptor substrate. These results prove that the B. subtilis γ-GT-catalyzed transpeptidation reaction is feasible, and the obsd. activities of γ-GT from B. subtilis could be interpreted in relation to the known ability of the enzyme to process the polymeric material, γ-polyglutamic acid.
pH-Dependent hydrolase, glutaminase, transpeptidase and autotranspeptidase activities of Bacillus subtilis γ-glutamyltransferase / C.F. Morelli, C. Calvio, M. Biagiotti, G. Speranza. - In: THE FEBS JOURNAL. - ISSN 1742-464X. - 281:1(2014), pp. 232-245.
|Titolo:||pH-Dependent hydrolase, glutaminase, transpeptidase and autotranspeptidase activities of Bacillus subtilis γ-glutamyltransferase|
MORELLI, CARLO (Corresponding)
BIAGIOTTI, MARCO (Penultimo)
SPERANZA, GIOVANNA (Ultimo)
|Parole Chiave:||γ-glutamyltransferase; Bacillus subtilis; enzyme catalysis; poly-γ-glutamic acid; transpeptidation reaction|
|Settore Scientifico Disciplinare:||Settore CHIM/06 - Chimica Organica|
|Data di pubblicazione:||2014|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1111/febs.12591|
|Appare nelle tipologie:||01 - Articolo su periodico|