Q. 37 Match the protein elution condition given in Group I with the appropriate chromatography matrices
from Group II.
Group I Group II
P Increasing concentration of sodium chloride i Phenyl-Sepharose
Q Increasing concentration of histidine ii Chromatofocusing
R Decreasing concentration of ammonium sulphate iii DEAE-Sephacryl
S Decreasing concentration of H
+ iv Ni-NTA
(A) P-iii; Q-iv; R-i; S-ii
(B) P-ii; Q-iv; R-i; S-iii
(C) P-i; Q-ii; R-iii; S-iv
(D) P-iv; Q-ii; R-iii; S-i
Master protein purification techniques through chromatography matching. This SEO-optimized guide covers elution conditions, matrices like DEAE-Sephacryl and Ni-NTA, and the correct answer for exam .
The correct answer for Q.37 is (A) P-iii; Q-iv; R-i; S-ii. This matching aligns standard protein purification principles where each elution condition targets specific matrix interactions in chromatography.
Core Matching Explained
Increasing NaCl concentration (P) elutes proteins from DEAE-Sephacryl (iii), an anion-exchange matrix, by disrupting ionic bonds through salt competition. Increasing histidine (Q) releases proteins from Ni-NTA (iv), a His-tag affinity matrix, via competitive ligand displacement. Decreasing ammonium sulfate (R) desorbs hydrophobic proteins from Phenyl-Sepharose (i) in hydrophobic interaction chromatography (HIC). Decreasing H+ (raising pH) separates proteins on Chromatofocusing (ii) based on isoelectric point differences.
Option Analysis
Each option tests knowledge of chromatography types. Use this table for quick comparison:
| Option | P (NaCl increase) | Q (Histidine increase) | R (Ammonium sulfate decrease) | S (H+ decrease) | Correct? |
|---|---|---|---|---|---|
| (A) | iii (DEAE-Sephacryl) | iv (Ni-NTA) | i (Phenyl-Sepharose) | ii (Chromatofocusing) | Yes |
| (B) | ii (Chromatofocusing) | iv (Ni-NTA) | i (Phenyl-Sepharose) | iii (DEAE-Sephacryl) | No |
| (C) | i (Phenyl-Sepharose) | ii (Chromatofocusing) | iii (DEAE-Sephacryl) | iv (Ni-NTA) | No |
| (D) | iv (Ni-NTA) | ii (Chromatofocusing) | iii (DEAE-Sephacryl) | i (Phenyl-Sepharose) | No |
Option (A) succeeds because it precisely links elution to matrix mechanisms: salt for ion-exchange, imidazole-like histidine for IMAC, salt decrease for HIC, and pH for chromatofocusing.
Chromatography Principles
Ion-exchange like DEAE-Sephacryl binds negatively charged proteins; NaCl gradient elutes by shielding charges. Ni-NTA captures His-tagged proteins; histidine competes for nickel binding sites. Phenyl-Sepharose uses high salt like ammonium sulfate for hydrophobic binding; decreasing it promotes elution. Chromatofocusing creates pH gradients; decreasing H+ (increasing pH) elutes proteins at their pI.
This setup is common in biotech exams for molecular biology and purification workflows. Practice with similar questions to master protein separation techniques.
