Abstract
Three different methods for hydrolysis and determination of amino acid composition of peptides and proteins were compared. We found, that the method of Matsubara and Sasaki (using 6N HCl and thioglycolic acid) gives comparatively low recoveries for tryptophan, while Liu and Chang's method, using p-toluenesulfonic acid and tryptamine, is more suitable. To eliminate the difficulties of the latter method, we used mercaptoethane-sulfonic acid, which, in the concentration used, results in total hydrolysis of peptide bonds within 22 hr and gives very high tryptophan recoveries. Both sulfonic acid methods were used for hydrolysis of the pentapeptide “pentagastrine” as well as of the proteins lysozyme, cytochrome c, and chymotrypsine. Their amino acid composition was determined using an automatic amino acid analyzer. Similarly to the p-toluenesulfonic acid method, the results of our method are totally reliable only for pure peptides and proteins, though the results obtained with our method using samples containing carbohydrates are better than those of all earlier methods.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
