Cycloleucine is an amino acid formed by cyclization of leucine. Cycloleucine is a non-metabolisable amino acid and is a specific and reversible inhibitor of nucleic acid methylation, and as such is widely used in biochemical experiments. [Wikipedia] (en)
# Herberg LJ, Rose IC: Effects of D-cycloserine and cycloleucine, ligands for the NMDA-associated strychnine-insensitive glycine site, on brain-stimulation reward and spontaneous locomotion. Pharmacol Biochem Behav. 1990 Aug;36(4):735-8. "Pubmed":http://www.ncbi.nlm.nih.gov/pubmed/2170997 (en)