W28 L2 - Enzyme Regulation and Inhibition

Flashcards on enzyme regulation, effectors, and inhibitors based on lecture notes.

What are effectors in the context of enzyme regulation?

Substances that have an effect on enzymes, influencing their regulation.

What defines a homotropic effector?

The effector is identical or very similar to the substrate.

• A homotropic effector is a molecule that binds to an enzyme at the active site, facilitating the enzyme's activity in a manner similar to the substrate.

How does substrate concentration affect reaction rate in Michaelis-Menten kinetics involving a homotropic effector?

The concentration of substrate directly influences the rate of the reaction; less substrate, slower rate; more substrate, faster rate up to Vmax.

What is positive cooperativity in enzyme kinetics?

When a substrate binds to one subunit of an enzyme, it makes it easier for subsequent substrate molecules to bind to other subunits.

What is substrate inhibition?

Too much substrate can decrease the reaction rate.

• This is because the active site or regulatory sites of the enzyme become saturated

What are heterotropic effectors?

Compounds that affect the enzyme but are not substrates.

What is a competitive inhibitor?

An inhibitor that interacts exclusively with the free enzyme, preventing substrate binding.

Why is it called a competitive inhibitor?

The inhibitor and substrate compete for the same binding site on the enzyme.

What is product inhibition?

The product of the reaction acts as an inhibitor.

What is an uncompetitive inhibitor?

An inhibitor that binds to the enzyme-substrate complex.

What is a mixed inhibitor?

An inhibitor that can bind to either the free enzyme or the enzyme-substrate complex.

What is a non-competitive inhibitor?

A mixed inhibitor with equal affinity for both the free enzyme and the enzyme-substrate complex, though likely doesn't exist in a true form