InterPro: IPR006000 Xylulokinase

The ability to metabolise xylose, one of the most abundant sugars in nature, is dependent on its conversion to xylulose-5-phosphate, which then enters the non-oxidative pentose phosphate pathway [1]. Xylulose-5-phosphate is produced from xylose by the sequential action of two enzymes; xylose isomerase, which converts xylose to xylulose, and xylulokinase, which subsequently phosphorylates xylulose.

This entry represents bacterial xylulokinase. In addition to its role in xylose metabolism this enzyme may also have a biosynthetic role. 1-deoxy-D-xylulose 5-phosphate serves as a precursor for the biosynthesis of the vitamins thiamine and pyridoxal and for the formation of isopentenyl pyrophosphate and dimethylallyl pyrophosphate via the nonmevalonate pathway of terpenoid biosynthesis. Xylulokinase catalyses the phosphorylation of 1-deoxy-D-xylulose at the hydroxy group of C-5 [2]. This reaction therefore constitutes a potential salvage pathway for the generation of 1-deoxy-D-xylulose 5-phosphate from exogenous or endogenous 1-deoxy-D-xylulose as starting material for the biosynthesis of terpenoids, thiamine and pyridoxal.