Question

Non-competitive inhibition of enzymes involve:

a. competition with substrate by binding to the regulatory (or allosteric) site

b. binding to the enyzme's regulatory (allosteric)

sites and alteration of the structure

c. binding to the enzyme's regulatory (allosteric) site

d. competition with the substrate to the same active site

e. alteration of the structure of the enzyme

Answer 1

Ans: Non-competitive inhibition is a type of enzyme inhibition where the inhibitor reduces the activity of the enzyme and binds equally well to the enzyme whether or not it has already bound the substrate.

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, but simply prevents product formation for a limited time.

In non-competitive inhibition, the inhibitor binds to an allosteric site and prevents the enzyme-substrate complex from performing a chemical reaction.

Non-competitive inhibition differs from uncompetitive inhibition in that it still allows the substrate to bind to the enzyme-inhibitor complex and form an enzyme-substrate-inhibitor complex, this is not true in uncompetitive inhibition, it prevents the substrate from binding to the enzyme inhibitor through conformational change upon allosteric binding.

So from all this literature we can conclude that the non-competitive inhibition involves binding to the enzyme's regulatory site without altering the enzyme's structure.

So option C is correct.