-!- Exists as two major isoenzymes; the A form preferentially oxidizes short-chain aliphatic hydroxy acids; the B form preferentially oxidizes long-chain and aromatic hydroxy acids. -!- The rat isoenzyme B also acts as EC 1.4.3.2. -!- Formerly EC 1.1.3.1.

-!- While all enzymes of this family oxidize the (S)-enantiomer of an alpha-hydroxy acid to an alpha-oxo acid, the ultimate oxidant (oxygen, intramolecular heme or some other acceptor) depends on the particular enzyme. -!- Transfers the electron pair from FMNH(2) to a component of the electron transport chain, most probably ubiquinone. -!- It is part of a metabolic pathway in Pseudomonads that allows these organisms to utilize mandelic acid, derivatized from the common soil metabolite amygdalin, as the sole source of carbon and energy. -!- Has a large active-site pocket and preferentially binds substrates with longer sidechains, e.g. 2-hydroxyoctanoate rather than 2-hydroxybutyrate. -!- It also prefers substrates that, like (S)-mandelate, have beta unsaturation, e.g. (indol-3-yl)glycolate compared with (indol-3- yl)lactate. -!- Esters of mandelate, such as methyl (S)-mandelate, are also substrates.