Sulfur-containing amino acids are essential building blocks of proteins that contain sulfur in their structure. The two primary sulfur-containing amino acids are cysteine and methionine. These amino acids play crucial roles in various biological processes, including protein synthesis and the formation of important molecules like glutathione, which helps protect cells from oxidative stress. Cysteine is unique because it can form disulfide bonds, which stabilize protein structures. Methionine, on the other hand, is often the first amino acid in protein synthesis and is vital for initiating the translation process. Both amino acids contribute to overall health and are important for various metabolic functions.