Pentose Phosphate Pathway

Front 1

What are the functions of the pentose phosphate pathway?

Back 1

1 The generation of NADPH
2 the production or Ribose-5-phosphate for nucleotide synthesis.
3 Provide an alternative to glycolysis to metabolize glucose
4. The interconversion of Pentose/hexoses

Front 2

Is ATP or NADPH utilized in this pathway in any way?

Back 2

ATP is not used or created. NADPH is produced by the pathway in reactions 1 and 3.

Front 3

What are the possible starting materials for this pathway?

Back 3

Glucose-6-phosphate

Front 4

What are the enzyme, substrate and product for this pathway?

Back 4

The first step is the rate limiting step.
G6P+NADP+--> 6-phosphoglucono-d-lactone + NADPH +H.
The enzyme is G6P dehydrogenase.

Front 5

Describe how glucose-6-phosphate dehydrogenase deficiency can relate to hemolytic anemia?

Back 5

Erythrocytes depend on NADPH in order to keep sufficient amounts of reduced glutathioneto protect the plasma membrane from being damaged by peroxidation of fatty acids in membrane lipids.

Without G6P dehydrogenase, the huge amounts of peroxides generated can overwhelm the glutathione peroxidase

Front 6

In what kinds of tissues is this pathway most active? In which part of the cell is it carried out?

Back 6

The most active tissues are those involved in biosynthesis of lipids or catecholamines, such as liver, adipose, lactating mammary, adrenal cortex and the nervous system (plus, bone marrow, skin and gastric mucosa)

It is carried out in the cytosol

Front 7

. What tissues require ribose phosphate for high rates of nucleotide synthesis?

Back 7

Bone marrow, skin and gastric mucosa

Front 8

What tissues require NADPH for lipid and catecholamine synthesis?

Back 8

Liver
Adipose
Lactating mammary
Adrenal cortex
Nervous system

Front 9

What tissues require NADPH for protection against oxidative damage?

Back 9

Erythrocytes, Leukocytes

Front 10

What types or categories of enzyme reactions are utilized in this pathway?

Back 10

Conversion of G6P to lactone (dehydrogenation with G6P dehydrogenase)

2.) Non-catalyzed conversion of lactone to gluconate

2.) 6-phosphogluconate to Ribulose 5 phosphate (oxidative decarboxylation, requiring NADP+)

3.) Ribulose-5-phosphate to X5P or R5P (isomerization and epimerization)

4.) X5P carbon-carbon cleavage or formation with transketoase

5.) Transaldoase reaction

6.) 2nd transaldoase reaction