Select the element constituent of amino acid, which is essential for synthesis of protein.

The element constituent of amino acid, Sulphur is essential for the synthesis of protein.
Sulphur-containing amino acids include methionine, cysteine, homocysteine, and taurine. Methionine and cysteine are classified as proteinogenic, canonic amino acids incorporated in protein structure.
Sulphur amino acids contribute substantially to the maintenance and integrity of the cellular systems by influencing the cellular redox state and the capacity to detoxify toxic compounds, free radicals and reactive oxygen species.