| N-AcetylCysteine (NAC, N-Acetyl-L-Cysteine) is the amino acid L-Cysteine plus an acetyl (-CO-CH3) group attached to the amino (NH2) group. The acetyl group functions to speed absorption and distribution on orally ingested cysteine. Amino acids which contain a sulfur group have antioxidant properties.
Glutathione (GSH, L-gamma-glutamyl-L-cysteinylglycine) is the predominant anti-oxidant in the aqueous cytoplasm of cells. Virtually all cells require glutathione for viability and function. Glutathione is synthesized from three amino acids in a two-step process, beginning with the combination of glutamic acid & cysteine and ending with the addition of glycine. The liver & lungs are the primary sites of glutathione synthesis. Glycine & glutamic acid are plentiful in cells, so it is the availability of cysteine that controls the reaction rate. Neuronal overexpression of the rate-limiting enzyme for glutathione synthesis in transgenic fruit flies has been shown to increase mean and maximum lifespan by up to 50% [JOURNAL OF BIOLOGICAL CHEMISTRY; Orr,WC; 280(45):37331-37338 (2005)]. |