Chapter 8.4: Other Functions of Nucleotides

• Hydrolysis of nucleoside triphosphates provides chemical energy.
• ATP is the most widely used for energy.
• When coupled to a reaction with a positive free energy change, ATP hydrolysis shifts the equilibrium to favor product formation.
• Hydrolysis of the ester linkage yields about 14 kJ/mol.
• Hydrolysis of each anhydride bond yields about 30 kJ/mol
• CTP hydrolysis can be a source of chemical energy
• Adenosine does not participate directly in the primary function, but its removal reduced cofactor activities.
• Nucleotide binding fold is a single protein domain that bonds adenosine.
• Coenzyme A

  
• Nicotinamide adenine dinucleotide, NAD+

  
• Flavin adenine dinucleotide, FAD

  
• Secondary messengers are compounds that are produced inside the cell following the interaction of extracellular chemical signals with receptors.
• Secondary messengers are often nucleotides, such as adenosine 3', 5'-cyclic monophosphate, or cAMP.
• ppGpp is produced in bacteria during amino acid starvation to inhibit the synthesis of the rRNA and tRNA molecules.
• Cyclic AMP, or cAMP

  
• Cyclic GMP, or cGMP

  
• Guanosine 5'-diphosphate, 3'-diphosphate, guanosine tetraphosphate, or ppGpp

  
• ATP and ADP serve as neurotransmitters in a variety of signaling pathways, signals for receptors that mediate pain sensation, or blood clotting signals.