In enzymology, a 2-alkyn-1-ol dehydrogenase (EC 1.1.1.165) is an enzyme that catalyzes the chemical reaction below:

2-butyne-1,4-diol + NAD⁺ ${\displaystyle \rightleftharpoons }$ 4-hydroxy-2-butynal + NADH + H⁺

The two substrates of this enzyme are 2-butyne-1,4-diol and NAD⁺, whereas its 3 products are 4-hydroxy-2-butynal, NADH, 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 2-butyne-1,4-diol:NAD⁺ 1-oxidoreductase.^[1]