Pereira, "The malate synthase of Paracoccidioides brasiliensis Pb01 is required in the glyoxylate cycle and in the allantoin degradation pathway," Medical Mycology, vol.
lutzii undergoes a global metabolic switch towards gluconeogenesis and ethanol production supported by precursors (acetyl-CoA, pyruvate, oxaloacetate, and succinate) from 6-oxidation, tricarboxylic acid (TCA), and glyoxylate cycles as a mechanism to adapt to carbon-starving conditions and survive in the hostile environment during macrophage infection.
There are no data in the literature on the energetic aspects involving lipid catabolism via the glyoxylate cycle. In this context, the present research investigated the relation between the amount of energy produced in the glyoxylate cycle, with fatty-acid-chain size, and compared energy efficiency in cells that use this approach, with the animal cells lacking the glyoxylate cycle.
The proposed equation was validated by comparing ATP amount obtained by its application, with ATP rates obtained by the addition of ATP amount produced by oxidative phosphorylation and substrate level phosphorylation in each step of the metabolic pathways that participate in the fatty acid degradation involving the glyoxylate cycle. The fatty acid degradation involves P-oxidation in glyoxysomes, glyoxylate cycle, Krebs cycle, part of gluconeogenesis and glycolysis, the pyruvate decarboxylation and again Krebs cycle (Figure 1).
The energy efficiency of fatty acids' degradation involving the glyoxylate cycle was compared with fatty acids' catabolism in animal cells.
ATP amount (x) resulting from glyoxysomal degradation of fatty acids with carbon number multiple of 4, followed by gluconeogenesis until phosphoenolpyruvate and its catabolism, to produce energy, may be calculated by the sum of ATP rates produced and consumed in [beta]-oxidation ([ATP.sub.[beta]-OX]), glyoxylate cycle ([ATP.sub.C GLYOX]), Krebs cycle ([ATP.sub.C KREBS) gluconeogenesis ([ATP.sub.OXAL-PEP]) and glycolysis /Krebs cycle again ([ATP.sub.PEP-CO2]), according to Equation (1):
The ATPs amount produced by [beta]-oxidation in glyoxylate cycle is given by Equation (2):
The regeneration of oxalacetate in glyoxylate cycle involves malate oxidation, which produces 1 NADH that yields 2.5 ATPs in oxidative phosphorylation (step B-5 in Figure 1).