Free amino acids are the building blocks of proteins and play critical roles in various biological processes. They are called ‘free’ because they exist in a form that is not bonded to other amino acids, meaning they do not form peptide bonds. A peptide bond is a type of covalent bond that links two amino acids together, forming a chain that eventually folds into a functional protein.
Amino acids have an amino group (–NH2), a carboxyl group (–COOH), and a side chain (R group) that makes each one unique. When two amino acids come together, the carboxyl group of one amino acid reacts with the amino group of another, leading to the elimination of a water molecule and the formation of a peptide bond. This process is called dehydration synthesis.
However, free amino acids do not participate in this reaction and remain unbound. Instead, they can be utilized by the body for various functions, such as being precursors for protein synthesis, serving as neurotransmitters, or participating in metabolism. Hence, free amino acids exist independently in the body, ready to be incorporated into proteins as needed.