In enzymology, a xylulokinase () is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are ATP and D-xylulose, whereas its two products are ADP and D-xylulose 5-phosphate.
This enzyme belongs to the family of transferases, specifically those transferring phosphorus-containing groups (phosphotransferases) with an alcohol group as acceptor. The systematic name of this enzyme class is ATP:D-xylulose 5-phosphotransferase. Other names in common use include xylulokinase (phosphorylating), and D-xylulokinase. This enzyme participates in pentose and glucuronate interconversions.
As of late 2007, two structures have been solved for this class of enzymes, with PDB accession codes and .
In 2014 a low-temperature , atmospheric-pressure enzyme-driven process to convert xylose into hydrogen with nearly 100% of the theoretical yield was announced. The process employs 13 enzymes, including xylulokinase.