Dihydrodipicolinate synthetase catalyzes, in higher plants chloroplast and in many bacteria, the first reaction specific to the biosynthesis of lysine and of diaminopimelate. DHDPS is responsible for the condensation of aspartate semialdehyde and pyruvate by a ping-pong mechanism in which pyruvate first binds to the enzyme by forming a Schiff-base with a lysine residue.

Two signature has been developed patterns for this enzyme and others related. The first one is centered on highly conserved region in the N-terminal part of these proteins. The second signature contains a lysine residue which has been shown to be the one that forms a Schiff-base with the substrate.
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