Amino Acids Amino acids with basic or acidic polar side chain. Amino acids with a uncharged polar side chain. Amino acids with a nonpolar side chain.
Amino acids consist exclusively of the L-isomer .
Normally there is free rotation about the C-N bond in amino acids. In proline and hydroxyproline, this free rotation is prevented. Cystine can form covalent bonds to another cystine. Protein shape is determined mostly by the amino acid sequence. Amino acids are covalently bonded from the carboxyl carbon of one amino acid to the amino nitrogen of another amino acid.