EC Explorer

4.3.3.7

4-hydroxy-tetrahydrodipicolinate synthase

pyruvate + L-aspartate-4-semialdehyde = (2S,4S)-4-hydroxy-2,3,4,5-tetrahydrodipicolinate + H₂O

dihydrodipicolinate synthase (incorrect), dihydropicolinate synthetase (incorrect), dihydrodipicolinic acid synthase (incorrect), L-aspartate-4-semialdehyde hydro-lyase (adding pyruvate and cyclizing), dapA (gene name).

L-aspartate-4-semialdehyde hydro-lyase [adding pyruvate and cyclizing; (4S)-4-hydroxy-2,3,4,5-tetrahydro-(2S)-dipicolinate-forming]

The reaction can be divided into three consecutive steps: Schiff base formation with pyruvate, the addition of L-aspartate-semialdehyde, and finally transimination leading to cyclization with simultaneous dissociation of the product. The product of the enzyme was initially thought to be (S)-2,3-dihydrodipicolinate [1,2], and the enzyme was classified accordingly as EC 4.2.1.52, dihydrodipicolinate synthase. Later studies of the enzyme from the bacterium Escherichia coli have suggested that the actual product of the enzyme is (2S,4S)-4-hydroxy-2,3,4,5-tetrahydrodipicolinate [3], and thus the enzyme has been reclassified as 4-hydroxy-tetrahydrodipicolinate synthase. However, the identity of the product is still controversial, as more recently it has been suggested that it may be (S)-2,3-dihydrodipicolinate after all [5].

created 1972 as EC 4.2.1.52, transferred 2012 to EC 4.3.3.7, modified 2020