Concept explainers
Interpretation:
The elution order of given amino acids with
Concept introduction:
Ion-exchange chromatography is used to separate mixture of amino acids on the basis of their overall charge by using cation or anion-exchange resins.
Dowex-1 is an anion-exchange resins with less polar used for anion-exchange chromatography.
Anion-exchange chromatography separate amino acids according to their
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CHEM 262 ORG CHEM EBOOK DIGITAL DELIVERY
- 22-49 Based on your knowledge of the chemical properties of amino acid side chains, suggest a substitution for leucine in the primary structure of a protein that would probably not change the character of the protein very much.arrow_forward22-61 Polyglutamic acid (a polypeptide chain made only of glutamic acid residues) has an a-helix conformation below pH 6.0 and a random-coil conformation above pH 6.0. What is the reason for this conformational change?arrow_forward22-71 Which amino acid side chain is most frequently involved in denaturation by reduction?arrow_forward
- 22-6 The members of which class of proteins are insoluble in water and can serve as structural materials?arrow_forward22-45 Proteins are least soluble at their isoelectric points. What would happen to a protein precipitated at its isoelectric point if a few drops of dilute HCl were added?arrow_forwardExplain why a protein is least soluble in an aqueous medium that has a pH equal to the isoelectric point of the protein.arrow_forward
- For aspartic and glutamic acids, the isoelectric point occurs at a pH where the net charge on the two carboxyl groups is -1 and balances the charge of +1 on the a-amino group. Calculate pI for these amino acids.arrow_forwardConsider the following peptide : Phe – Glu – Ser – Met and Val – Trp – Cys – Leu. Do these peptides have different net charges at (a) pH 1? (b) pH 7? Indicate the charges at both pH valuesarrow_forwardArginine has three ionizable groups. The pk of a-COOH is 2.18; a-NH 3 +, 9.09; and the R-group, 13.20. What is the charge of arginine at pH = 12? 0 -2arrow_forward
- Each ionizable group of an amino acid can exist in one of two states, charged or neutral. The electric charge on the functional group is determined by the relationship between its pKą and the pH of the solution. This relationship is described by the Henderson-Hasselbalch equation. Histidine has three ionizable functional groups. Complete the equilibrium equations by assigning the proper pKą for each ionization and the net charge on the histidine molecule in each ionization state. H || H,N*-C-C-OH H|| H,N*-C-C-o- H|| H,N*-C-C-o- H|| H,N-C-C-o- CH, CH, CH, CH, HN HN N -NH -NH -NH -NH Answer Bank pK, = 6.0 -1 pк, - 9.17 +2 -2 +1 pK, = 7.59 pK, = 1.8 %3D 1 1arrow_forwardComplete the table for the ionizable groups of the fictitious amino acid hypothetinine. Group alpha-amino alpha-carboxyl Ka 5.24 x 10-⁹ 2.13 x 10-3 pKa (to TWO decimals) 8.9 2.7 Average charge of group when pH=pK (to ONE decimal) -0.5 +0.5arrow_forwardConsider the formation of a dimeric protein 2P ->P2 At 25.0 °C , the enthalpy of the reaction is 17 kj/mol and the entropy of the reaction is 65 j/kmol. Is the dimerization favored at this temperature ? Thermodynamically speaking, explain/support your answer. Show work.arrow_forward
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