Mechanism
Non-competitive inhibition models a system where the inhibitor and the substrate may both be bound to the enzyme at any given time. When both the substrate and the inhibitor are bound, the enzyme-substrate-inhibitor complex cannot form product and can only be converted back to the enzyme-substrate complex or the enzyme-inhibitor complex. Non-competitive inhibition is distinguished from general mixed inhibition in that the inhibitor has an equal affinity for the enzyme and the enzyme-substrate complex.
The most common mechanism of non-competitive inhibition involves reversible binding of the inhibitor to an allosteric site, but it is possible for the inhibitor to operate via other means including direct binding to the active site. It differs from competitive inhibition in that the binding of the inhibitor does not prevent binding of substrate, and vice versa, it simply prevents product formation for a limited time.
This type of inhibition reduces the maximum rate of a chemical reaction without changing the apparent binding affinity of the catalyst for the substrate (Kmapp – see Michaelis-Menten kinetics).
Read more about this topic: Non-competitive Inhibition
Famous quotes containing the word mechanism:
“The law isn’t justice. It’s a very imperfect mechanism. If you press exactly the right buttons and are also lucky, justice may show up in the answer. A mechanism is all the law was ever intended to be.”
—Raymond Chandler (1888–1959)
“When one of us dies of cancer, loses her mind, or commits suicide, we must not blame her for her inability to survive an ongoing political mechanism bent on the destruction of that human being. Sanity remains defined simply by the ability to cope with insane conditions.”
—Ana Castillo (b. 1953)
“A mechanism of some kind stands between us and almost every act of our lives.”
—Sarah Patton Boyle, U.S. civil rights activist and author. The Desegregated Heart, part 3, ch. 2 (1962)