Oxidoreductase with an extremely broad substrate specificity that can reduce reversibly 2-oxocarboxylates to (2R)-hydroxycarboxylates. A + a (2R)-2-hydroxycarboxylate = a 2-oxocarboxylate + AH2 Binds 1 [4Fe-4S] cluster per subunit. Binds 1 Mo-molybdopterin (Mo-MPT) cofactor per subunit. Is inhibited by cyanide. Is sensitive to oxygen. Forms various types of homooligomers. Belongs to the AOR/FOR family.