Racemases

Racemases are a group of enzymes that rearrange hydrogen on the single chiral carbon atom of a compound. They belong to the group of isomerases .

L -alanine [synonym: ( S ) -alanine] (left) and D -alanine [synonym: ( R ) -alanine] (right) are configuration isomers of the amino acid alanine. Racemases can convert D -alanine into L -alanine.

Biological importance

A biological significance of racemases in bacteria , in which amino acids of the L - in the D - configuration are and converted back. This is important because, among other things, the peptidoglycan bacterial cell wall contains the amino acids alanine and glutamine in the D configuration. D -amino acids occur in non-ribosomal peptides .

The proteinogenic amino acids in eukaryotes - with the exception of achiral glycine - are exclusively L -configured.

Medical importance

The bacterial alanine racemase can be inhibited by the antibiotic cycloserine ( D -4-amino-3-isoxazolidinone). It is z. B. used in the treatment of tuberculosis .

See also

• Racemate

Individual evidence

1. ^ Albert Gossauer : Structure and reactivity of biomolecules , Verlag Helvetica Chimica Acta, Zurich, 2006, p. 450, ISBN 978-3-906390-29-1 .