title: Substrate specificity of galactokinase from Streptococcus pneumoniae TIGR4 towards galactose, glucose, and their derivatives.
abstract: Galactokinases (GalKs) have attracted significant research attention for their potential applications in the enzymatic synthesis of unique sugar phosphates. The galactokinase (GalKSpe4) cloned from Streptococcus pneumoniae TIGR4 presents a remarkably broad substrate range including 14 diverse natural and unnatural sugars. TLC and MS studies revealed that GalKSpe4 had relaxed activity towards galactose derivatives with modifications on the C-6, 4- or 2-positions. Additionally, GalKSpe4 can also tolerate glucose while glucose derivatives with modifications on the C-6, 4- or 2-positions were unacceptable. More interestingly, GalKSpe4 can phosphorylate L-mannose in moderate yield (43%), while other L-sugars such as L-Gal cannot be recognized by this enzyme. These results are very significant because there is rarely enzyme reported that can phosphorylate such uncommon substrates as l-mannose.
authors.affiliation: The State Key Laboratory of Microbial Technology, National Glycoengineering Research Center and Department of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zou
authors.forename: Wenjun
authors.initials: W
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Cai
authors.forename: Leilei
authors.initials: L
authors.lastname: Chen
authors.forename: Mengyang
authors.initials: M
authors.lastname: Xue
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Zhang
authors.forename: Jie
authors.initials: J
authors.lastname: Shen
authors.forename: Min
authors.initials: M
authors.lastname: Chen
mesh_terms: D002855:Chromatography, Thin Layer; D005686:Galactokinase / Q000378:metabolism*; D005690:Galactose / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D013058:Mass Spectrometry; D010766:Phosphorylation; D013296:Streptococcus pneumoniae / Q000201:enzymology*; D013379:Substrate Specificity
chemical_list: D005686:Galactokinase; D005947:Glucose; D005690:Galactose