Aspartate-semialdehyde dehydrogenase

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aspartate-semialdehyde dehydrogenase
EC number
CAS number 9000-98-0
IntEnz IntEnz view
ExPASy NiceZyme view
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Gene Ontology AmiGO / EGO

In enzymology, an aspartate-semialdehyde dehydrogenase (EC is an enzyme that is very important in the biosynthesis of amino acids in prokaryotes, fungi, and some higher plants. It forms an early branch point in the metabolic pathway forming lysine, methionine, leucine and isoleucine from aspartate. This pathway also produces diaminopimelate which plays an essential role in bacterial cell wall formation. There is particular interest in ASADH as disabling this enzyme proves fatal to the organism giving rise to the possibility of a new class of antibiotics, fungicides, and herbicides aimed at inhibiting it.

The enzyme catalyzes the reversible chemical reaction

L-aspartate 4-semialdehyde + phosphate + NADP+ \rightleftharpoons L-4-aspartyl phosphate + NADPH + H+

The 3 substrates of this enzyme are L-aspartate 4-semialdehyde, phosphate, and NADP+, whereas its 3 products are L-4-aspartyl phosphate, NADPH, and H+. In physiological conditions however, the reaction runs in the opposite direction. This enzyme belongs to the family of oxidoreductases, specifically those acting on the aldehyde or oxo group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is L-aspartate-4-semialdehyde:NADP+ oxidoreductase (phosphorylating). Other names in common use include aspartate semialdehyde dehydrogenase, aspartic semialdehyde dehydrogenase, L-aspartate-beta-semialdehyde:NADP+ oxidoreductase, (phosphorylating), aspartic beta-semialdehyde dehydrogenase, and ASA dehydrogenase. This enzyme participates in glycine, serine and threonine metabolism and lysine biosynthesis.

Aspartate-semialdehyde dehydrogenase may be cis-regulated by an Asd RNA motif found in the 5' UTR of some Asd genes.

Structural studies[edit]

As of late 2007, 24 structures have been solved for this class of enzymes, with PDB accession codes 1BRM, 1GL3, 1MB4, 1MC4, 1NWC, 1NWH, 1NX6, 1OZA, 1PQP, 1PQU, 1PR3, 1PS8, 1PU2, 1Q2X, 1T4B, 1T4D, 1TA4, 1TB4, 1YS4, 2EP5, 2GYY, 2GZ1, 2GZ2, and 2GZ3.


  • BLACK S, WRIGHT NG (1955). "Aspartic beta-semialdehyde dehydrogenase and aspartic beta-semialdehyde". J. Biol. Chem. 213 (1): 39–50. PMID 14353904. 
  • Boyer, P.D., Lardy, H. and Myrback, K. (Eds.), The Enzymes, 2nd ed., vol. 7, Academic Press, New York, 1963, p. 203-221.