Triose kinase

Triose kinase is an enzyme in the liver that takes part in an alternate glycolytic pathway. It phosphorylates a three-carbon sugar (or triose) to allow it to continue along the standard glycolytic pathway.

The preceding step, also differing from normal glycolysis, involves the conversion of fructose 1-phosphate to dihydroxyacetone phosphate and glyceraldehyde, essentially splitting a six-carbon sugar into two three-carbon sugars. The normal glycolytic reaction involves an additional phosphate on the glyceraldehyde (i.e., glyceraldehyde 3-phosphate, from fructose 1,6-bisphosphate). Thus, the liver pathway must phosphorylate the triose. Triose kinase catalyzes this step using ATP.

The following step in the pathway is the standard glycolytic step, catalyzed by triose phosphate isomerase.