A. In affinity chromatography, lectins are used to purify a glycoprotein

B. The separation in gel filtration chromatography is based on size, shape and net charge of the protein

C. In ion exchange chromatography, the bound proteins are eluted using NaCl solution

D. In affinity chromatography, the binding of a protein to a ligand is by specific non-covalent interactions

All three options A, C, and D are correct statements about chromatography techniques, but B contains an inaccuracy regarding gel filtration principles.

Option Analysis

• A. In affinity chromatography, lectins are used to purify a glycoprotein: Correct. Lectins are carbohydrate-binding proteins immobilized on the matrix to specifically bind glycosylated proteins via glycan recognition, a standard biospecific application.

• B. The separation in gel filtration chromatography is based on size, shape and net charge of the protein: Incorrect. Gel filtration (size exclusion chromatography) separates solely by hydrodynamic volume, which reflects size and shape; net charge plays no role as there’s no charge interaction with the neutral matrix.

• C. In ion exchange chromatography, the bound proteins are eluted using NaCl solution: Correct. NaCl increases ionic strength, competing with protein-matrix electrostatic bonds for elution via salt gradient.

• D. In affinity chromatography, the binding of a protein to a ligand is by specific non-covalent interactions: Correct. Binding relies on reversible non-covalent forces like hydrogen bonds, van der Waals, and hydrophobic interactions.

Incorrect Statement: B

Introduction to Protein Chromatography Statements

Identifying the incorrect statement on protein chromatography methods is key for GATE Life Sciences students mastering purification techniques like affinity, gel filtration, and ion exchange. These methods exploit specific protein properties for separation, with common pitfalls in principles like separation basis.

Core Principles of Key Chromatography Types

Affinity chromatography uses biospecific ligand-protein non-covalent binding (e.g., lectins for glycoproteins). Ion exchange relies on charge for NaCl elution. Gel filtration separates by size/shape via porous matrix exclusion, independent of charge.

Breakdown of Statements

Statement B misstates gel filtration, making it the incorrect one.