In enzymology, a GDP-6-deoxy-D-talose 4-dehydrogenase (EC 1.1.1.135) is an enzyme that catalyzes the chemical reaction

GDP-6-deoxy-D-talose + NAD(P)+ ${\displaystyle \rightleftharpoons }$ GDP-4-dehydro-6-deoxy-D-mannose + NAD(P)H + H⁺

The 3 substrates of this enzyme are GDP-6-deoxy-D-talose, NAD⁺, and NADP⁺, whereas its 4 products are GDP-4-dehydro-6-deoxy-D-mannose, NADH, NADPH, and H⁺.

This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD⁺ or NADP⁺ as acceptor. The systematic name of this enzyme class is GDP-6-deoxy-D-talose:NAD(P)⁺ 4-oxidoreductase. This enzyme is also called guanosine diphospho-6-deoxy-D-talose dehydrogenase. This enzyme participates in fructose and mannose metabolism.

• Markovitz A (July 1964). "Biosynthesis of guanosine diphosphate D-rhamnose and guanosine diphosphate D-talomethylose from guanosine diphosphate alpha-D-mannose". The Journal of Biological Chemistry. 239: 2091–8. PMID 14209931.