2. HMP SHUNT
Contents to be discuss;
A Short Introduction
AND
Steps Involved in HMP Shunt Pathway
3. INTRODUCTION
0 This cycle is an alternative pathway to glycolysis and
TCA cycle for the oxidation of glucose.
0 HMP shunt is more anabolic in nature.
0 It is responsible for the biosynthesis of NADPH and
pentoses (riboses).
0 These pentoses and NADPH are responsible for the
biosynthesis of various important biological
molecules (DNA, RNA, Fatty acids and Steroids).
4. Cytosol – is the fluid, filled in cells in which chemical reactions takes
place.
Cell
6. STEPS INVOLVED IN HMP SHUNT
--Which are helps in biosynthesis of important biological molecules
7. Step - I
0 Glucose-6-phosphate in the presence of NADP+ and
the enzyme glucose 6-phosphate dehydrogenase forms
6-phospho-glucono- δ-lactone.
0 The first molecule of NADPH+ is produced in this step.
8. Step - II
0 The 6-phospho glucono-δ-lactone is unstable and the
ester spontaneously hydrolyses to 6- phosphogluconate.
0 The enzyme that catalyses the reaction is gluconolactone
hydrolase.
9. Step - III
0 6-phospho gluconate further undergoes dehydrogenation
and decarboxylation by 6-phosphogluconate dehydrogenase
to form the ketopentose, D-ribulose 5-phosphate.
0 This reaction generates the second molecule of NADPH.
10. Step - IV
0 The enzyme phosphopentose isomerase converts ribulose
5-phosphate to its aldose isomer, D-ribose 5- phosphate.
12. Significances of
HMP Shunt
Pentoses
(Riboses)
Nucleic acids
(RNA and DNA)
Nucleotides
(ATP, FAD, NAD+
and CoA
NADPH
-Fatty acids,
-Steroids,
-Amino acids,
-Required for the Phagocytosis,
-Helps in detoxification of drugs
and foreign particles,
-Maintains the concentration of
Glutathione
