Chapter 39, Problem 39.1CR

What are two common ways by which signal transduction pathways enhance the activity of specific enzymes?

Summary Introduction

To determine: The two common ways by which signal transduction pathways promotes specific enzyme activity.

Introduction: De-etiolation is called as greening process. When a newly growing stem breaks the ground and reaches the surface, it gets light. Signal transmission is the second step during de-etiolation. The light received by the receptors is transmitted by second messengers to activate the specific enzymes.

Explanation of Solution

Signal transduction is the process of conversion of an extracellular signal into an intracellular signal. It involves a cascade of molecules that transfer the information. In signal transduction process, two second messengers are utilized to activate two specific proteins namely kinases 1 and 2. They are cyclic guanosine monophosphate (cGMP) and calcium ions (Ca²⁺).

Immediately after the reception of light, one pathway utilizes cyclic GMP and activates the specific protein namely kinase 1. The other pathway opens the Ca²⁺ channels and increases Ca²⁺ ions to pass into the cell, which in turn activates the specific protein such as kinase 2. Hence, there are two common ways for the enhancement of activity of specific enzymes.