Allosteric Enzymes: Characteristics, Models, and Examples

Arpaporn Sutipatanasomboon

Introduction

Allosteric enzymes are a group of biocatalysts that possess common characteristics of an enzyme but do not exhibit a typical Michaelis-Menten kinetic behavior. Instead, their kinetics follow a sigmoid curve.
The key to allosteric enzyme activity lies in the reversible binding to a specific molecule on a non-catalytic site of the enzyme. The binding initiates the formation of enzyme-substrate complexes and promotes or hinders successive binding activities.
Allosteric enzymes are one of the regulatory enzymes, which act as the pathway’s rate-determining step and control the overall rate of the metabolic pathway.

How Do Enzymes Control Cellular Activities?

Enzymes are regarded as the keys that control cellular activities. A single cellular task is accomplished through a series of interconnected biochemical reactions in the metabolic pathway. Each reaction must take place in sequence and be catalyzed by a specific enzyme that only acts upon its substrate.

The resulting product from the catalyzed reaction typically acts as the substrate of the next reaction. Thus, the abundance and the activity of the enzymes in the corresponding pathway influence the metabolic flux, or the turnover rate of the metabolites, which, in turn, affect the overall cellular activities.^[1]

The overall rate of the entire metabolic pathway is governed by one chemical reaction of the pathway called thet

Stereotaxic/ Impact Models

Amplify & Separate