Question

Kinases are enzymes that transfer a phosphoryl group from a nucleoside triphosphate. Which of the following are valid kinase-catalyzed reactions?

(a)$\mathbf{ATP}\mathbf{+}\mathbf{GDP}\mathbf{\to }\mathbf{ADP}\mathbf{+}\mathbf{GTP}$

(b)$\mathbf{ATP}\mathbf{+}\mathbf{GMP}\mathbf{\to }\mathbf{AMP}\mathbf{+}\mathbf{GTP}$

Short answer

(a) Yes, $\mathrm{ATP}+\mathrm{GDP}\to \mathrm{ADP}+\mathrm{GTP}$it is a kinase-catalyzed reaction.

(b) No,$\mathbf{ATP}\mathbf{+}\mathbf{GMP}\mathbf{\to }\mathbf{AMP}\mathbf{+}\mathbf{GTP}$is not a kinase-catalyzed reaction.

Step-by-step solution

Introduction

Kinase-catalyzed reactions are chemical processes that are catalyzed by kinases. Kinases are enzymes that transfer one phosphoryl group from a nucleoside triphosphate to organic molecules.

By phosphorylating other proteins, the kinases enzymes change their structure. Adenosine triphosphate (ATP) is the main source of phosphoryl groups (ATP).

Explanation for (a)

The enzyme nucleoside diphosphate kinasecatalyzes the formation of ADP from ATP. An ATP molecule splits in this process and one of the phosphate groups from ATP is transferred to Adenosine Diphosphate (ADP). Thus, $\mathbf{ATP}\mathbf{+}\mathbf{GDP}\mathbf{\to }\mathbf{ADP}\mathbf{+}\mathbf{GTP}$is a valid kinase-catalyzed reaction.$\mathbf{ATP}\mathbf{+}\mathbf{GDP}\mathbf{\to }\mathbf{ADP}\mathbf{+}\mathbf{GTP}$

Explanation for (b)

In$\mathbf{ATP}\mathbf{+}\mathbf{GMP}\mathbf{\to }\mathbf{AMP}\mathbf{+}\mathbf{GTP}$reaction,only two ADP molecules and two inorganic phosphates are required to create AMP (Pi). Two ATP molecules should be broken down to produce 2 Pi, yet only one ATP molecule is broken down in this process. Thus, this reaction is not a valid kinase-catalyzed reaction.