Multiple Choice
Which of the following best describes the 'induced fit' model of enzyme-substrate interaction?
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6. Enzymes and Enzyme Kinetics
Lock and Key Vs. Induced Fit Models
Multiple Choice
In the context of the lock-and-key vs. induced-fit models, how does an enzyme recognize and bind its substrate?
A
By requiring ATP hydrolysis to create a substrate-binding pocket for every binding event
B
By randomly colliding with any molecule and permanently reshaping the substrate into a matching form before binding occurs
C
By binding only substrates that form covalent bonds with the active site as the primary recognition step
D
By having an active site whose shape and chemical properties are complementary to the substrate, and in the induced-fit model the active site can change conformation upon substrate binding to improve complementarity
Verified step by step guidance1
Understand that enzymes recognize and bind substrates primarily through the active site, which has a specific shape and chemical environment complementary to the substrate.
In the lock-and-key model, the active site is considered a rigid structure that fits the substrate exactly, like a key fitting into a lock, emphasizing shape complementarity without major changes upon binding.
In the induced-fit model, the active site is flexible and can undergo conformational changes when the substrate binds, enhancing the fit and stabilizing the enzyme-substrate complex.
Recognize that substrate binding does not require ATP hydrolysis or permanent reshaping of the substrate before binding; instead, binding is driven by non-covalent interactions and conformational adjustments of the enzyme.
Note that covalent bonding is not the primary recognition step; rather, the enzyme-substrate interaction relies on complementary shape and chemical properties, with induced fit allowing dynamic adaptation to the substrate.
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