Catalyzes the NAD-dependent oxidation of either all-trans-retinol or 9-cis-retinol (PubMed:17279314). Also oxidizes long chain omega-hydroxy fatty acids, such as 20-HETE, producing both the intermediate aldehyde, 20-oxoarachidonate and the end product, a dicarboxylic acid, (5Z,8Z,11Z,14Z)-eicosatetraenedioate (PubMed:16081420). Also catalyzes the reduction of benzoquinones (PubMed:10514444). all-trans-retinol + NAD(+) = all-trans-retinal + H(+) + NADH 9-cis-retinol + NAD(+) = 9-cis-retinal + H(+) + NADH 20-oxo-(5Z,8Z,11Z,14Z)-eicosatetraenoate + H2O + NAD(+) = (5Z,8Z,11Z,14Z)-eicosatetraenedioate + 2 H(+) + NADH 20-hydroxy-(5Z,8Z,11Z,14Z)-eicosatetraenoate + NAD(+) = 20-oxo-(5Z,8Z,11Z,14Z)-eicosatetraenoate + H(+) + NADH 1,4-benzoquinone + H(+) + NADH = hydroquinone + NAD(+) Binds 2 Zn(2+) ions per subunit. Oxydation of 20-HETE is inhibited by low concentrations of N-heptylformamide (PubMed:16081420). Oxydation of 20-HETE is a decreased by 55-65% by either all-trans-retinol or all-trans-retinoic acid. Strongly inhibited by omega-hydroxy fatty acids (By similarity). Homodimer. There are 7 different ADH's isozymes in human: three belongs to class-I: alpha, beta, and gamma, one to class-II: pi, one to class-III: chi, one to class-IV: ADH7 and one to class-V: ADH6. Belongs to the zinc-containing alcohol dehydrogenase family. Class-II subfamily.