Aspartate-semialdehyde dehydrogenase
In enzymology, aspartate-semialdehyde dehydrogenase 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
The substrates of this enzyme are L-aspartic-4-semialdehyde, phosphate, and oxidised nicotinamide adenine dinucleotide phosphate. Its products are phosphoaspartic acid, reduced NADPH, and a proton. Under physiological conditions, the reaction proceeds in the direction from phosphoaspartate to the aldehyde.
This enzyme belongs to the family of oxidoreductases, specifically those acting on the aldehyde or oxo group of a donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is L-aspartate-4-semialdehyde:NADP+ oxidoreductase . Other names in common use include aspartate semialdehyde dehydrogenase, aspartic semialdehyde dehydrogenase, L-aspartate-beta-semialdehyde:NADP+ oxidoreductase, , 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.