👉 Cysteines are a group of amino acids in the protein chain that play important roles in the formation and function of proteins. They form part of the alpha helix structure of proteins, which is responsible for their stability, folding, and interactions with other proteins. Cysteine is also involved in several cellular processes including DNA repair, cell division, and energy metabolism. Cysts are often associated with certain types of cancer, such as lung, breast, and prostate cancers. The presence of