Figure 5. Pentose Phosphate Pathway and redox homeostasis.

The central panel shows a schematic representation of the oxygen-dependent metabolic modulation mechanism.⁴¹ Oxidative stress and increased pO₂ during storage in AS-3 is expected (and previously observed¹⁰) to trigger activation of the pentose phosphate pathway (PPP ON) to recycle oxidized glutathione (GSSG) back to the reduced form (GSH). However, this mechanism is progressively impaired during storage^10,35 and should be negatively affected by anaerobiosis^6,36. On the other hand, anaerobiosis should slow Fenton and Haber-Weiss reactions by removing oxygen, a key substrate for pro-oxidant reactions. No significant effect was observed in terms of redox homeostasis in response to anaerobiosis (either in presence or absence of CO₂). Metabolic intermediates of the non-oxidative phase of the pentose phosphate pathway (see text) increased in response to total anaerobiosis (AN). Solid line=AN, Dotted line=AN[CO₂], Dashed line=Control