Amino acid derivatives are compounds that are formed from amino acids, which are the building blocks of proteins. These derivatives can be created through various chemical modifications, such as methylation or phosphorylation, altering the original amino acid's structure and function. They play crucial roles in biological processes, including neurotransmission and metabolism. Common examples of amino acid derivatives include serotonin, derived from tryptophan, and dopamine, derived from tyrosine. These derivatives often act as signaling molecules in the body, influencing mood, behavior, and various physiological functions. Understanding these compounds is essential for studying biochemistry and pharmacology.