The common property of all proteins is that they consist of long chains of amino alpha amino acids the general structure of amino acids is shown in the amino acids are so called because the carbon atom in the molecule carries an amino group nh 2 the carbon atom also carries a carboxyl group cooh. Chemical properties of polypeptides biosynthesis of proteins evolutionary and genetic origins of protein sequences physical interactions that determine the properties of protein sequences physical interactions that determine the properties of proteins conformational properties of polypeptide chains the folded conformations of globular proteins proteins in solution and in membranes interactions with other molecules enzyme catalysis degradation. The average molecular weight of an amino acid is taken to be 110 the total number of amino acids in a protein multiplied by 110 gives the approximate molecular weight of that protein different proteins have different amino acid composition and hence their molecular weights differ the molecular weights of proteins range from 5000 to 109 daltons. The average molecular weight of an amino acid is taken to be 110 the total number of amino acids in a protein multiplied by 110 gives the approximate molecular weight of that protein different proteins have different amino acid composition and hence their molecular weights differ