Interest in the noncoenzymatic properties of NAD+ has rekindled interest in NAD+ biosynthesis. In the last two years, at least five publications have schematized NAD+ biosynthesis in yeast as shown in Figure 1 (Panozzo et al. 2002, Sandmeier et al. 2002, Bitterman et al. 2002, Anderson et al. 2003, Gallo et al. 2004). This scheme depicts a convergence of the flux to NAD+ from de novo synthesis, nicotinic acid import, and nicotinamide salvage at NaMN. This is somewhat surprising because biochemists from 1950 to the present day have been characterizing the Nma1 and Nma2 gene products from yeast and their human homologs as NMN adenylyltransferases (Kornberg 1950, Emanuelli et al. 1999, Emanuelli et al. 2003, Garavaglia et al. 2002) or as dual specificity enzymes that will use either NaMN or NMN as a substrate (Zhou et al., 2002).