‘Lock and Key model’ of enzyme action was proposed by
**Core Concept**
The "Lock and Key" model of enzyme action is a fundamental concept in biochemistry that describes the mechanism of enzyme-substrate interaction. This model proposes that enzymes have specific binding sites that fit onto the substrate molecule, similar to a lock and key fitting together. This precise interaction enables the enzyme to catalyze a specific chemical reaction.
**Why the Correct Answer is Right**
The "Lock and Key" model was first proposed by Emil Fischer in 1894. According to this model, the enzyme has a unique shape and structure that allows it to bind specifically to the substrate molecule. This binding is facilitated by the presence of specific functional groups on the enzyme that complement the functional groups on the substrate. The binding of the substrate to the enzyme induces a conformational change in the enzyme, which positions the substrate for optimal catalysis. This model is still widely used today to describe the specificity of enzyme-substrate interactions.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the "Lock and Key" model was not proposed by Paul Ehrlich, who is known for his work on immunology and chemotherapy.
**Option B:** This option is incorrect because the "Induced Fit" model was proposed by Daniel Koshland, not the "Lock and Key" model.
**Option C:** This option is incorrect because the "Conformational Change" model is a related concept, but it is not the same as the "Lock and Key" model.
**Option D:** This option is incorrect because the "Substrate Enzyme Complex" is a general term that refers to the complex formed between an enzyme and its substrate, but it is not a model of enzyme action.
**Clinical Pearl / High-Yield Fact**
The "Lock and Key" model highlights the importance of enzyme specificity in biochemical reactions. Enzymes are highly specific because their binding sites are shaped to fit only one specific substrate molecule, allowing for precise control over chemical reactions in the body.
**Correct Answer: C. Emil Fischer**