However, substrate specificity can be incorporated by unstabilizing the E*S complex which largely has to do with the E state. This is true for many serine proteases which all do the exact same reaction. As hinted by your professor, enzymes will perform their function in the lock-key mechanism. The induced fit model is more appropriately used to understand the mechanisms of substrate specificity.
Unfortunately, the majority of biochemistry textbook continue to teach using the induced fit model since it is a much easier concept to understand given the majority of undergrads and 1st year graduates' understanding of statistical thermodynamics. Long story short, the induced fit model is a good explanation of how enzymes morph into an active state but depending on how you frame the mechanism, you are always seeing a lock-key model (at least according to my enzymology professor). When the substrate is added to the system, it will stablize the lock and thermodynamically favor an ES state. Thermodynamically, this means that the "lock" always exists but it is an unstable configuration.
#Lock and key concept free#
According to the below figure, this would imply that the E S state always exists but as it is a few kcals higher in free energy, the state is rarely seen. In the lock and key model, the E state will be equivalent to the ES state. Using the above description the induced fit model (E) will change its structure to the E S model. (apologies since this is the only figure that I could find to explain this concept).
In that manner, a protein will adopt both the unbound active state shown in the induced fit model and the complementary shape shown in the lock and key model. As mentioned by proteins are highly dynamic. Thousands of new, high-quality pictures added every day. Both models are true depending on how you frame the mechanisms of catalysis. 43,094 3d Lock And Key Concept Images, Stock Photos & Vectors Shutterstock Find 3d Lock And Key Concept stock images in HD and millions of other royalty-free stock photos, illustrations and vectors in the Shutterstock collection.
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