 Background: Homocarnosine beta-alanine - gamma-aminobutyric acid is one of the most abundant dipeptides in the brain. It has important antioxidant properties. Both beta-alanine and GABA are neurotransmitters, suggesting that cleavage of this dipeptide by carnosine dipeptidase 1 CNDP1 may have important regulatory functions in vivo. 