Acid hydrolysis of peptides and proteins

The lyophilized protein is dissolved or suspended in 1 to 2 ml of 5.7 N HCl, which is usually prepared by glass distillation, repeated 

After hydrolysis is complete the tubes are cooled, scored and opened, and the acid is removed, either by rotary evaporation or in a heated desiccator over NaOH at 40-50°C. In our laboratory it is standard procedure to examine 1/10 of each hydrolysate by high-voltage paper electrophoresis at pH 1.9 (see Appendix I) prior to analysis to ensure that appropriate amounts are analyzed. Some amino acid derivatives (oxidation products of methionine, methylated lysines, etc.) are also sometimes observed by this procedure. It is usually helpful to add an internal standard, either prior to hydrolysis to reveal hydrolytic losses or prior to analysis to reveal analytical losses. For this purpose we have used norleucine (0.03 pmoles). This amino acid elutes after leucine on the 60 cm column. 

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A Tsugita, T Uchida, HW Mewes, T Ataka. Rapid vapor-phase acid (hydrochloric acid and trifluoroacetic acid) hydrolysis of peptide and protein. J Biochem 102 1593-1597, 1987. 

Partial Acid Hydrolysis of Peptides and Proteins Containing Disulfide Bonds... 

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