The characterisation of a galactokinase from Streptomyces coelicolor

Abstract

Promiscuous galactokinases (GalKs), which catalyse the ATP dependent phosphorylation of galactose in nature, have been widely exploited in biotechnology for the rapid synthesis of diverse sugar-1-phosphates. This work focuses on the characterisation of a bacterial GalK from Streptomyces coelicolor (ScGalK), which was overproduced in Escherichia coli and shown to phosphorylate galactose. ScGalK displayed a broad substrate tolerance, with activity towards Gal, GalN, Gal3D, GalNAc, Man and L-Ara. Most interestingly, ScGalK demonstrated a high activity over a broad pH and temperature range, suggesting that the enzyme could be highly amenable to multi-enzyme systems.

Keywords: Galactokinase; Streptomyces coelicolor; Substrate specificity; Sugar-1-phosphates.