Biochemistry - Length of peptide chain

[Aisha_18]

How would you detemine the length of an amino acid chain from a formalin titration of a hydrolyzed an unhydrolyzed peptide. My ratio of carboxylic groups came out to be 2.5, but how do i determine the chanin length givien this information?

[CharonY]

Ok, so you are aware what you actually measure with this method (carboxylic groups). How many free carboxylic group does e.g. an intact dipeptide possess. How many if it is hydrolyzed?