From genome sequence data you know that there is no other related kinase that could compensate for the loss of the kinase in muscle cells. Although the kinase gene may have been knocked out in the above experiment, the protein that binds to the regulatory site in common with the two genes is still expressed. Therefore, expression of the essential muscle specific gene has not been affected. Some are covalently linked to the enzyme while others are less tightly bound. For example adenine nucleotides such as NADH and FAD are components of a number of coenzymes.
Nucleotides are carriers of activated intermediates in many biosynthetic processes.
For example UDP-glucose is the activated glucose donor in the synthesis of glycogen. Nucleotides are carriers of chemical energy ATP is the most important cellular energy source. Its easily hydrolyzed acid anhydride bond. Nucleotides function as metabolic regulators and signaling molecules in the cell 1. GTP is a regulator of G protein coupled receptor signaling.