Amino acid composition analysis generally requires a higher purity of the product, it can give the type and number of amino acids in the peptide. The analysis process first destroys the peptide bonds by acid hydrolysis, the typical acid hydrolysis condition is: under vacuum conditions, 110 degrees C, with 6M hydrochloric acid hydrolysis 16 to 72 hours. Although acid hydrolysis is useful, incomplete amino acid analysis cannot be obtained under acid hydrolysis conditions, because the side chains of temporamide and glutamine contain amide bonds, and the acid used to cut off the protein peptide bonds can also convert temporamide into winteramine, glutamine into glutamate.
Due to the high hydrolysis temperature, tryptophan's ring is easily oxidized by the air, and even in a sealed tube, the mozzarella ring of tryptophan is almost destroyed. Therefore, the content of tryptophan protein is often estimated by its ultraviolet absorption spectrum, and the content of tryptophan can also be analyzed by alkali hydrolysis. Cysteine can not be accurately measured in acid hydrolysis, to accurately measure the need for oxidation or methylation before protein hydrolysis, the resulting derivatives can be quantified after acid hydrolysis.