M20 Peptidase D has specificity for beta-alanyl-L-histidine dipeptide
Peptidase M20 family, Peptidase D (PepD, Xaa-His dipeptidase; X-His dipeptidase; aminoacylhistidine dipeptidase; dipeptidase D; Beta-alanyl-histidine dipeptidase; pepD g.p. (Escherichia coli); EC 3.4.13.3) subfamily. PepD is a cytoplasmic enzyme family characterized by its unusual specificity for the dipeptides beta-alanyl-L-histidine (L-carnosine or beta-Ala-His) and gamma-aminobutyryl histidine (L-homocarnosine or gamma-amino-butyl-His). Homocarnosine has been suggested as a precursor for the neurotransmitter gamma-aminobutyric acid (GABA), acting as a GABA reservoir, and may mediate anti-seizure effects of GABAergic therapies. It has also been reported that glucose metabolism could be influenced by L-carnosine. PepD also includes a lid domain that forms a homodimer; however, the physiological function of this extra domain remains unclear.
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