Eric Niederhoffer

SIU-SOM

What is the role of the pentose phosphate pathway?

Overview

• NADPH productionGlutathione reduction (E), fatty acid/cholesterol synthesis (L)

• Glycolytic intermediatesFructose-6-phosphate, glyceraldehyde-3-phosphate

• Ribose-5-phosphateNucleotide synthesis (nucleated cells)

Glycolysis and Pentose Phosphate Pathways

PPP

NADPH

6PG

3-7 C metabolites(R5P, F6P, G3P)

G6PDHlactonase6PGDH

CO2

NADP+ + H+

GSH

GSSGGR

GP

H2O2 H2O

Glc

Pyr

G6P

1,3-BPG

3PG

HK

PGI

PK

F6P

DHAP + G3P

PFK

aldolaseF16BP

2PG

PEP

PGK

PGM

enolase

G3PDH

Glycolysis

Oxidative Phase

Glucose G6PHK

F6PPGI

G6PDH

6PGL

NADPHNADP+

lactonase

6PG

•FA/cholesterol synthesis•RBC ox stress

CO2

6PGDH

Ru5P

NADPHNADP+

Non-oxidative Phase

Ru5P

Xu5P

RuP3E

R5P

R5PI

TK

S7P

G3PTA

E4P

F6P

TK

F6P

G3P

Glycolysis Nucleotides

Review Questions

• What are the main functions of the

pentose phosphate pathway?

• Which enzymes produce NADPH?

• Which intermediates can feed back

into the glycolytic pathway?