The percentage of each amino acid present in a polypeptide chain can be determined by ion-exchange chromatography, using the compound ninhydrin as a visualization agent. a.(i) Describe the conditions used to prepare the polypeptide chain for chromatography and
(ii) explain why these conditions result in the inability to determine the order of amino acids in a polypeptide. (5 points):
b.(i) Draw a simplified structure of an example ion-exchange chromatography resin and
(ii) explain how the resin is able to separate amino acids.
c. (i) Explain the physical process of how amino acids are separated and identified using column chromatography. Be sure to briefly mention (1) what kind of procedure is used, (2) what kind of data you would collect, and (3) what conclusion you would draw from that data.
d. Aside from visualization, (i) explain why ninhydrin is used in chromatography but is not used to identify an amino acid. As part of your explanation, (ii) draw the structure of the complex formed between an amino acid and ninhydrin (you do not need to show any mechanisms).