proteinogenic amino-acid biosynthesis L-lysine biosynthesis GO:0009085 This pathway represents the biosynthesis of the basic amino-acid L-lysine. L-lysine biosynthesis is peculiar because it has two different anabolic routes that evolved separately in organisms, the diaminopimelate (DAP) and aminoadipate (AAA) pathways. The DAP pathway synthesizes L-lysine from aspartate and pyruvate, and diaminopimelate is an intermediate. The DAP pathway is utilised by most bacteria, some archaea, some fungi, some algae, and plants. The AAA pathway synthesizes L-lysine from 2-oxoglutarate (alpha-ketoglutarate) and acetyl coenzyme A (acetyl-CoA), and L-alpha-aminoadipate is an intermediate. The AAA pathway is utilised by most fungi, some algae, the bacterium Thermus thermophilus, and probably some archaea, such as Sulfolobus, Thermoproteus, and Pyrococcus [source: InterPro]. No organism is known to possess both pathways [PMID:20418392]. L-lysine is one of the 10 essential amino-acids that mammals are unable to synthesize, and must therefore acquire in their diets. PMID:12355264 pathway L-2,6-diaminohexanoate biosynthesis UPa:UPA00404 PMID:20418392 2,6-diaminohexanoic acid biosynthesis