MethionineÕs three major metabolic roles are as a Methyl and a Sulphur donor and a precursor to other Sulphur Amino Acids such as Cysteine and Taurine. It is required in the structure of Nucleic Acid, Collagen formation and protein synthesis of cells. Amino Acids are essential to health. Most form the small structural components of protein and are required for the synthesis of protein within the body. The primary function of most Amino Acids is to furnish the essential material for duplication of the genetic code, for cell division, and for the formation of muscles and connective tissue.