These six are arginine, cysteine, glycine, glutamine, proline and tyrosine. These six are arginine, cysteine, glycine, glutamine, proline, and tyrosine. Alanine, glycine, and serine bind to the glutamate substrate site. Serine, formed from 3-phosphoglycerate, is the precursor of glycine and cysteine. Consequently, residues such as alanine, glycine and valine tend to be preferred. Multiple nutrients fuel one-carbon metabolism, including glucose, serine, glycine, and threonine. The connective tissue protein elastin also has a high percentage of both glycine and alanine. Other inhibitors/regulators are glycine and alanine. It is unrelated to the amino acid glycine. GHB is a precursor to GABA, glutamate, and glycine in certain brain areas. No significant difference in glutamate and glycine activity from the effects of chlorpromazine were reported. Strychnine is a neurotoxin which acts as an antagonist of glycine and acetylcholine receptors. Glycine and leucine were discovered in 1820. The genus name is not related to the amino acid glycine. Conjugation of unmodified lipoic acid to glycine was detected especially in mice.