Pentose Phosphate Pathway. Generation of NADPH and Pentoses. M.F.Ullah , Ph.D. COURSE TITLE : BIOCHEMISTRY 2 COURSE CODE : BCHT 202. PLACEMENT/YEAR/LEVEL: 2nd Year/Level 4, 2nd Semester. Function of PPP: 1. NADPH production
Pentose Phosphate Pathway
COURSE CODE: BCHT 202
PLACEMENT/YEAR/LEVEL: 2nd Year/Level 4, 2nd Semester
Characteristics of PPP:Oxidative and Non-oxidative Phases
NADPH producing reactions
Pentose phosphate and glycolytic intermediates producing reactionsNon-oxidative phase of Pentose Phosphate Pathway
Reactive Oxygen Species
Reactive oxygen species are highly reactive derivatives of oxygen that are formed by the transfer of electrons from redox active molecules (with high electron transfer potential) to molecular oxygen.
Example : Superoxide anion , Hydrogen peroxide
Detoxification of Superoxide Anion and Hydrogen Peroxide
Cells have a number of antioxidant enzymes which remove reactive oxygen species
and therefore protect the cells from oxidative injury
G6PDH Deficiency and Hemolytic Anemia
Hemolytic anemia is a disorder in which the red blood cells are destroyed prematurely.
Hemolytic anemia is often inherited, such as Glucose-6-Phosphate Dehydrogenase deficiency (G6PD).
G6PD enzyme functions in the Pentose-Monophosphate shunt and catalyzes the production of NADPH which is required in the detoxification of the harmful oxidant H2O2 by glutathione antioxidant system.
Red cells deficient in G6PD are unable to produce NADPH to neutralize hydrogen peroxide - H2O2 converts to hydroxyl radicals and this can lead to oxidative damage/toxic injury.
Heinz bodies, aggregates of cross-linked hemoglobin, form on the cell membranes and
subject the cell to mechanical stress as it tries to go through small capillaries. The action of the
ROS on the cell membrane as well as mechanical stress from the lack of deformability result in hemolysis.