A chromatographic technique which separates one protein from another based on the difference in their size is
**Core Concept**
Separation of proteins based on size is a fundamental concept in biochemistry and molecular biology. This technique relies on the principle of size exclusion, where smaller molecules can pass through a porous matrix, while larger molecules are excluded and elute later.
**Why the Correct Answer is Right**
The correct answer is based on the principle of size exclusion chromatography, where proteins are separated based on their size. In this technique, a porous matrix is used as the stationary phase, and the proteins are separated based on their ability to pass through the pores. Proteins with smaller sizes can enter the pores and interact with the matrix, while larger proteins are excluded and elute later. This technique is commonly used in biochemistry and molecular biology to separate and purify proteins based on their size.
**Why Each Wrong Option is Incorrect**
**Option A:** Gel filtration chromatography is a technique that separates proteins based on size, but it is not the correct answer because the question specifically asks for a chromatographic technique. Gel filtration is a type of size exclusion chromatography, but the question is asking for the general term.
**Option B:** Ion exchange chromatography separates proteins based on charge, not size. This technique is useful for separating proteins with different isoelectric points.
**Option C:** Affinity chromatography separates proteins based on their ability to bind to a specific ligand, not size. This technique is useful for purifying proteins that have a specific binding site.
**Clinical Pearl / High-Yield Fact**
Size exclusion chromatography is a useful technique for separating and purifying proteins based on their size, but it is not suitable for separating proteins with similar sizes. In such cases, other chromatographic techniques like ion exchange or affinity chromatography may be more useful.
**Correct Answer: D. Size exclusion chromatography**