In enzymology, a formaldehyde transketolase () is an enzyme that catalyzes the chemical reaction D-xylulose 5-phosphate + formaldehyde glyceraldehyde 3-phosphate + glycerone Thus, the two substrates of this enzyme are D-xylulose 5-phosphate and formaldehyde, whereas its two products are glyceraldehyde 3-phosphate and glycerone. This enzyme belongs to the family of transferases, specifically those transferring aldehyde or ketonic groups (transaldolases and transketolases, respectively). The systematic name of this enzyme class is D-xylulose-5-phosphate:formaldehyde glycolaldehydetransferase. This enzyme is also called dihydroxyacetone synthase. This enzyme participates in methane metabolism. It employs one cofactor, thiamin diphosphate. References EC 2.2.1 Thiamine enzymes Enzymes of unknown structure