The large scale production of organic acids by micro-organisms The theoretical limits are 1.0 (all ATP)and 0(all AMP)with a normal working range of 0.75 to 0.9. The involvement of energy charge in the integration and regulation of metabolism is considered further in the BIOTOL text entitled 'Biosynthesis and the Integration of Cell Metabolism After revising the tCa cy ctions in more detail we shall return to the subject of metabolic control by ATP Figure 5.2 shows a detailed version of the TCA cycle indicating cofactor changes and the individual intermediates ace h) A NADH+H malate cIs-aconrtate fumarate f FAD NADH +H succinate CoASH a-oxoglutarate GTP. NAD ADP succinyl CoA NADH +H ATP CoA+3 NAD++ FAD+ADP + Pi 2 CO +3 NADH +3H++FADH +ATP +CoASH Figure 5.2 The tricarboxylic acid cycle Enzymes: a)citrate synthase; b )aconitase; c)isocitrate dehydrogenase; d)a-oXoglutarate dehydrogenase; e) succinyl CoA synthetase; f) succinate dehydrogenase; g)fumarase; h) malate dehydrogenase; i) nucleoside diphosphokinase 5.2.3 The control of metabolism In section 5. 2. 2 we considered a simple equation expressing the energy charge of the cell in terms of the ratio of adenine nucleotides. Figure 5.3 summarises the principal allosteric enzymes of glycolysis and the tCa cycle and indicates how the individual adenine nucleotides influence the activity of a variety of enzymes. The enzymes to the right of the glucose to pyruvate pathway are those involved in glycolysis; those to the eft are involved in gluconeogenesis, ie the synthesis of glucose from pyruvatThe large scale production of organic acids by micro-organisms 123 The theoretical limits are 1.0 (all ATP) and 0 (all AMP) with a nod working range of 0.75 to 0.9. The involvement of energy charge in the integration and regulation of metabolism is considered further in the BIOTOL text entitled 'Biosynthesis and the Integration of Cell Metabolism'. After revising the TCA cycle reactions in more detail we shall return to the subject of metabolic control by ATP. Figure 5.2 shows a detailed version of the TCA cycle indicating cofactor changes and the individual intermediates. Figure 5.2 The tricarboxylic acid cycle. Enzymes: a) citrate synthase; b) aconitase; c) ismitrate dehydrogenase; d) a-oxoglutarate dehydrogenase; e) succinyl CoA synthetase; f) succinate dehydrogenase; g) fumarase; h) malate dehydrogenase; i) nucleoside diphosphokinase. 5.2.3 The control of metabolism In section 5.2.2 we considered a simple equation expressing the energy charge of the cell in terms of the ratio of adenine nucleotides. Figure 5.3 summarises the principal allosteric enzymes of glycolysis and the TCA cycle and indicates how the individual adenine nucleotides influence the activity of a variety of enzymes. The enzymes to the right of the glucose to pyruvate pathway are those involved in glycolysis; those to the left are involved in gluconeogenesis, ie the synthesis of glucose from pyruvate-