Chapter 19, Problem 19.67AP

Interpretation Introduction

Interpretation:

The purpose of positive and negative regulation should be discussed.

Concept Introduction:

Enzyme:

• It is a protein or a molecule which can act as a catalyst for a biological reaction.
• Does not affect the equilibrium point of the reaction.
• Active site of the enzyme is the region where the reaction takes place.
• Enzyme’s activity can be specific which means the activity is limited to a certain substrate and a certain type of reaction and it is referred to as specificity of the enzyme.

Enzyme regulation can be done by two ways: Allosteric control and feedback inhibition.

Allosteric control:

• In this type of regulation, the binding of a molecule at one site on a protein affects the binding of another molecule at a different site.
• Allosteric enzymes have more than one protein chain and two kinds of binding sites.
• One binding site is for the substrate and other is for regulation.
• The advantage is that regulators need not be structurally similar to the substrate because they do not bind to the active site.
• Can be either positive or negative

Positive regulation: It is a type of regulation in which binding a positive regulator changes an unavailable active site so that substrate can fit into the active site and the reaction occurs.

Negative regulation: Binding a negative regulator changes the active site so that the enzyme can no longer bind substrate to the active site.