Glutathione Metabolism in Yeasts and Construction of the Advanced Producers of This Tripeptide Springer Nature Link Methionine an overview ScienceDirect Topics Homocysteine and methionine are key amino acids with a vital connection to glutathione one of your body's most important substances! Methionine is abundant in many foods, so protein isn't the culprit, Critical Roles of the CysteineGlutathione Axis in the Production of Glutamyl Peptides in the Nervous System