ID 1.1.1.304 DE diacetyl reductase [(S)-acetoin forming]. AN (S)-acetoin dehydrogenase. CA (S)-acetoin + NAD(+) = diacetyl + H(+) + NADH. CC -!- The reaction is catalyzed in the reverse direction. CC -!- This activity is usually associated with butanediol dehydrogenase CC activity (EC 1.1.1.4 or EC 1.1.1.76). CC -!- While the butanediol dehydrogenase activity is reversible, diacetyl CC reductase activity is irreversible. CC -!- This enzyme has been reported in the bacteria Geobacillus CC stearothermophilus, Enterobacter aerogenes and Klebsiella pneumoniae. CC -!- Different from EC 1.1.1.303. CC -!- Formerly EC 1.1.1.5. DR Q9ZNN8, BUDC_CORGT ; Q48436, BUDC_KLEPN ; Q04520, BUDC_RAOTE ; DR Q5HJP2, BUTA_STAAC ; P66775, BUTA_STAAM ; P99120, BUTA_STAAN ; DR Q6GKH9, BUTA_STAAR ; Q6GCZ8, BUTA_STAAS ; P66776, BUTA_STAAW ; DR Q5HKG6, BUTA_STAEQ ; Q8CQD2, BUTA_STAES ; //