Free energy for nucleotide addition in transcription

Range -3.5 kcal/mol
Organism Generic
Reference Encyclopedia of Biological Chemistry, e-only, S-H Jun, B A Warner, and K S Murakami, The Pennsylvania State University, University Park, PA, USA, RNA Polymerase Reaction in Bacteria, 2013 Elsevier Inc p.167 right column top paragraph
Comments "The nucleotide addition is accomplished through the formation of a phosphodiester bond and release of pyrophosphate (PPi) as a by-product. The free energy for this reaction is rather small (?G=–3.5 kcal/mol), but additional free energy is provided in vivo by rapidly hydrolyzing PPi into two phosphate groups by enzyme pyrophosphatase that makes the entire reaction highly energetically favorable (?G=–7 kcal/mol BNID 109865) under physiological condition, which is practically irreversible."
Entered by Uri M
ID 109864