NAD biosynthesis I from aspartate (Escherichia coli)

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As a general rule, most prokaryotes utilize the aspartate de novo pathway, in which the nicotinate moiety of NAD is synthesized from aspartate [Begley01], while in eukaryotes, the de novo pathway starts with tryptophan [Panozzo02] (NAD biosynthesis II (from tryptophan)). The first attempt to elucidate a prokaryotic pathway to NAD was reported by Ortega and Brown in 1960 [Ortega60]. They implicated (incorrectly) glycerol and a dicarboxylic acid as precursors in the synthesis of the pyridine ring of NAD in E. coli. Subsequent work by Chandler et al. [Chandler70] established that L-aspartate is the dicarboxylic acid precursor. Suzuki et al., in 1973, established that the three carbon precursor is dihydroxyacetone phosphate (DHAP) and not glycerol [Suzuki73]. In addition, Andreoli et al. demonstrated that quinolinate was a key intermediate in this pathway [Andreoli63]. Eventually it became clear that quinolinate is indeed a precursor, not only in this pathway, but in all known NAD biosynthetic pathways.