xtures of amino acids can be analyzed by separating the mixture into its compone
ID: 140330 • Letter: X
Question
xtures of amino acids can be analyzed by separating the mixture into its components through ion- exchange chromatography. Amino acids placed on a cation-exchange resin containing sulfonate (-SO3) groups flow down the column at different rates because of two factors that influence their movement: (1) ionic attraction between the sulfonate groups on the column and positively charged functional groups on the amino acids, and (2) hydrophobic interactions between amino acid side chains and the strongly hydrophobic backbone of the polystyrene resin. For each pair of amino acids listed, determine the order of elution from a cation exchanger in pH 7.0 buffer. Amino Acid PairElutes First Asp and Lys Arg and Met Ala and Glu Gly and Leu Phe and Ser Asp Met Glu Leu Ser Elutes Second Lys Arg Ala Gly PheExplanation / Answer
Ion exchange chromatography is defined as a process which is used to separate ions and polar molecules based on their affinity to the ion exchanger. There are two types of ion exchange chromatography which are anion-exchange and cation-exchange. In cation-exchange chromatography, the stationary phase is negatively charged and positively charged molecules are loaded to be attracted to it. In anion-exchange chromatography, the stationary phase is positively charged and negatively charged molecules are loaded to be attracted to it.
For each pair of amino acids, the order of elution from a cation-exchanger in pH 7.0 buffer is as follows:
1. As the stationary phase is negatively charged the positively charged amino acids will be attracted towards the negatively charged. Thus, Asp being negative charge will elute first while Lys being positive charge will be eluted second.
2. In this case, Met being non-polar will elute first and Arg being positive charge will elute second.
3. Glu being negative charge will elute first and Ala elutes second.
4. Leu will elute first and Gly will elute second.
5. Phe will elute first and Ser elutes second.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.