Substrate specificity of galactokinase from Streptococcus pneumoniae TIGR4 towards galactose, glucose, and their derivatives
作者:Yang Zou、Wenjun Wang、Li Cai、Leilei Chen、Mengyang Xue、Xiaomei Zhang、Jie Shen、Min Chen
DOI:10.1016/j.bmcl.2012.03.095
日期:2012.5
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. (C) 2012 Elsevier Ltd. All rights reserved.