Sanne de Bruin

128 Chapter 5 Figure 1. Overview metabolic pathways involving glucose and glutathione in erythrocytes Pentose phosphate pathway and glutathione metabolism The pentose phosphate pathway (PPP) consists of two parts, the oxidative phase and the non-oxidative phase (see figure 1). The non-oxidative part of the PPP consists of multiple reactions, which are responsible for the conversion of ribose-5P into glycolysis intermediates and vice versa. The main function of the oxidative PPP in erythrocytes is the production of the reduced electron carrier nicotinamide adenine dinucleotide phosphate (NADPH). NADPH is converted from oxidized nicotinamide adenine dinucle- otide phosphate (NADP+) during the oxidative phase while converting glucose-6P into ribulose-5P. NADPH is a cofactor for many reactions. In erythrocytes it is, among other things, essential for the reduction of GSH. GSH plays an important role in neutralizing reactive oxygen species (ROS) and is therefore essential during oxidative stress. Because