T'he RlR, strain of Jlr. tub~rcukosis utilized nicotiriic acid for the synthesis of nicotiilamide adenine dinucleotide (NAII). Nicotiriic acid moiionucleotide (KalLIN) and nicotinic acicl cliiiucleoticlc (NaAI)) were identified among the enzymatic reaction i~iixture products. A rorlaparisoil with J f . bnzis de~nonstrated a greater capacity for N:ID syntllesis by the bovine bacillus. I t has been hypothesizeci that reduced NAL) synthesis and failure to utilize intermediates which continue to be procl~nced are responsible for the excessive nicotinic acicl accuraulation by t u b e r c~~l n~i s .