Protein molecules are biological macromolecules formed by many amino acids connected by peptide bonds. Physiologically functional proteins in the body are all ordered structures. Each protein has a certain percentage of amino acid mass, the sequence of amino acids, and the specific arrangement position of the peptide chain space. Therefore, the protein molecular structure composed of the sequence of amino acids and the spatial arrangement of peptide chains is the structural basis for each protein to have a unique physiological function. https://www.creative-proteomics.com/pronalyse/protein-primary-structure-characterization-methods.html