Energy charge

In order to detect the power status of a cell with a single measure, has Daniel Atkinson the concept of energy charge (Engl. Energy charge ) was introduced. The energy charge describes the ratio of all adenosyl nucleotides and reaches the maximum value 1 for the (hypothetical) case that only ATP is present. In reality, the value ranges between 0.75 and 0.95. It is kept in this area by key regulatory enzymes in the energy metabolism. A prominent example is phosphofructokinase

1. ${\displaystyle {\text{Energieladung}}={\frac {[{\mbox{ATP}}]+{\frac {1}{2}}[{\mbox{ADP}}]}{[{\mbox{ATP}}]+[{\mbox{ADP}}]+[{\mbox{AMP}}]}}}$
2. ${\displaystyle 2\ ADP\longrightarrow ATP+AMP}$

Definition of the energy charge

The evaluation of ADP as ½ ATP follows from the fact that enzymes such as myokinase (muscle) or adenylate kinase can provide one molecule of ATP from two molecules of ADP (equation 2).

Additional parameters and other applications

The information on adenosine phosphates is expediently supplemented with information on free phosphate and NADPH in order to obtain comprehensive information about the energy and redox status of organelles, cells and tissues, which allows conclusions to be drawn about the activity of processes of primary metabolism .

credentials

1. ↑ Daniel E. Atkinson, Energy charge of the adenylate pool as a regulatory parameter. Interaction with feedback modifiers, Biochemistry, 1968, 7 (11), pp 4030-4034
2. ↑ Heldt, HW, Chon, CJ, Maronde, D., Herold, A., Stankovic, ZS, Walker, DA, Kraminer, A., Kirk, MR and Heber, U .: Role of orthophosphate and other factors in regulation of starch formation in leaves and isolated chloroplasts. - Plant Physiology 59: 1146-1155, 1977
3. ↑ Stuhlfauth, T., Beckedahl, J. and Fock, HP: The response of energy charge, NADPH and free phosphate pools on water stress, Photosynthetica 25 (1): 11-15, 1991