MOLECULE

Cysteinylglycine

Cysteinylglycine, also known as CG or cys-gly, belongs to the class of organic compounds known as dipeptides. These are organic compounds containing a sequence of exactly two alpha-amino acids joined by a peptide bond. As this dipeptidase also hydrolyzes the glutathione metabolite cysteinylglycine, the therapeutic association of imipenem and cilastatin causes plasma levels of cysteinylglycine to increase significantly, while cysteine levels are decreased and homocysteine levels are unaffected. Cysteinylglycine is a naturally occurring dipeptide composed of cysteine and glycine. Imipenem (thienamycin formamidine) is a broad-spectrum beta-lactam antibiotic, always used in combination with cilastatin in order to avoid the premature breakdown of imipenem by renal tubular dipeptidase. It is derived from the breakdown of glutathione (a tripeptide). Cysteinylglycine is a very strong basic compound (based on its pKa). Cysteinylglycine exists in all living species, ranging from bacteria to humans. The damage process seems to be related to an overproduction of oxygen reactive species inducing an oxidative perturbation with an increase in some oxidized forms (disulfides and protein mixed disulfides) and a decrease in free thiols (PMID: 15895891). Outside of the human body, Cysteinylglycine has been detected, but not quantified in, several different foods, such as garlics, sweet rowanberries, butternut squash, common oregano, and pepper (c. frutescens). This could make cysteinylglycine a potential biomarker for the consumption of these foods. Cysteinylglycine, with regard to humans, has been linked to the inborn metabolic disorder phenylketonuria. Therefore, antibiotic treatment using imipenem-cilastatin induces important metabolic changes that should not remain unrecognized (PMID: 15843241). In plasma, cysteinylglycine is in a reduced, oxidized, and protein-bound form (aminothiol) and interacts via redox and disulphide exchange reactions in a dynamic system referred to as redox thiol status (PMID: 8642471). The detrimental effect on embryo quality of a high homocysteine (Hcy) concentration in the ejaculate and in the follicular fluid is intriguing and may suggest that Hcy is inversely associated with fertility outcome (PMID: 16556671). Cysteinylglycine is expected to be in Cannabis as all living plants are known to produce and metabolize it.