D-alanine biosynthetic process

Definition

Target type: biologicalprocess

The chemical reactions and pathways resulting in the formation of D-alanine, the D-enantiomer of the amino acid alanine, i.e (2R)-2-aminopropanoic acid. [GOC:jsg, GOC:mah]

The D-alanine biosynthetic process is an essential pathway in bacteria and some archaea. It converts L-alanine, a common amino acid, into D-alanine, a stereoisomer of L-alanine, crucial for the synthesis of peptidoglycan, the major component of bacterial cell walls.

The process begins with the conversion of L-alanine to pyruvate by the enzyme alanine racemase. This reaction involves a reversible isomerization of the chiral center of alanine, changing its configuration from L to D. The mechanism involves the formation of a Schiff base intermediate between the amino group of L-alanine and the pyridoxal phosphate cofactor bound to alanine racemase. This intermediate undergoes proton exchange and tautomerization, leading to the formation of D-alanine.

The D-alanine generated through this pathway is then utilized by other enzymes in the peptidoglycan biosynthesis pathway. Specifically, D-alanine is incorporated into the peptide cross-links that connect peptidoglycan strands, providing structural integrity to the bacterial cell wall.

The D-alanine biosynthetic process is a key target for antibacterial drugs. Inhibition of alanine racemase or other enzymes involved in the pathway can effectively disrupt peptidoglycan synthesis, leading to cell lysis and bacterial death. Many antibiotics, such as the cyclic peptide antibiotics, target the D-alanine biosynthetic process.
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Proteins (2)

Compounds (1)