PENTOSE PHOSPHATE PATHWAY

PENTOSE PHOSPHATE PATHWAY

-THE IDEAL SUBSTITUTE OF GLYCOLYSIS

ABOUT THE PATHWAY

GOAL

To generate NADPH

• Also known as phosphogluconate pathway /hexose monophosphate shunt/ oxidative pentose pathway.
• The pentose phosphate pathway is a metabolic pathway parallel to glycolysis which generates NADPH and pentoses (5-carbon sugars) as well as ribose 5-phosphate.

To synthesize 5-C sugars

TAP HERE

-LOCATION-

PLASTIDS (IN PLANTS)

ADRENAL CORTEX

CYTOSOL OF LIVER CELLS

LACTATING MAMMARY GLANDS

PATHWAY-

PURPOSE OF THE PATHWAY-

• Function as an alternative route for glucose oxidation.
• Supply pentoses to NADPH for fatty acid synthesis.,and to reduce glutathione.
• Generation of ribose-5-phosphate
• Key role in both reductive biosynthesis and protection from oxidative stress by glutathione.

Substrate: Glucose-6-phosphate.

1. First stage= Oxidative phase (NADPH is generated)
2. Second stage= Non-oxidative (Synthesis of 5-C sugar).

• First four reactions are Irreversible and Oxidative
• And the next are Reversible

STEPS-

TAP HERE

REGULATION-

Key enzyme = Levels of enzyme is increased in the liver when large amounts of carbohydrates are consumed. INHIBITOR- NADPH and palmitoyl-CoA STIMULATOR- NADP+

GLUCOSE-6-PHOSPHATE DEHYDROGENASE

2 molecules of NADPH and 1 molecule of R5P

ENERGY YIELD-