Lecture 22. Phosphorylated compounds
Tuesday 16 April 2019
Free energy of hydrolysis and phosphoryl group transfer potential. The example of ATP. Other phosphorylated compounds and their phosphoryl group transfer potentials. Energetic coupling by means of group transfer reactions.
Reading: Lehninger - Ch.13, pp.507-517.
Summary
Reading summary.
§13.3 Phosphoryl group transfers and ATP.
The free-energy change for ATP hydrolysis is large and negative.
Worked example 13-2: Calculation of ΔGp (phosphorylation potential).
Other phosphorylated compounds and thioesters also have large free energies of hydrolysis.
Table 13-6: Standard free energies of hydrolysis of some phosphorylated compounds
and acetyl CoA (a thioester).
ATP provides energy by group transfers, not by simple hydrolysis.
ATP donates phosphoryl, pyrophosphoryl, and adenylyl groups.
Assembly of informational macromolecules requires energy
ATP energizes active transport and muscle contraction.
Box 13-1 Firefly flashes: Glowing reports of ATP (p.515).
Transphosphorylations between nucleotides occurs in all cell types.
Inorganic pyrophosphate is a potential phosphoryl group donor.
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Supplementary and additional resources: Phosphate and phosphoryl groups; Bioenergetics; Thioesters.