G6P DH

Question 1

Where is G6P D found?

Answer 1

cytoplasm

Question 2

G6P D is present in all cells

Answer 2

ya

Question 3

what does G6P D require as a cofactor>

Answer 3

NADP

Question 4

Catalyzes the first rxn of the PPP

Answer 4

ya (G6P +NADP–>6-phosphoglucono-delta-lactone+NADPH)

Question 5

How many subunits is G6P D composed of?

Answer 5

2-4

Question 6

Regulation of G6P D

Answer 6

inhib by high NADPH

Question 7

Where is the G6P D gene found?

Answer 7

On the X chromosome

Question 8

What is G6PD the regulatory enzyme of?

Answer 8

PPP

Question 9

How can ROS be produced from normal metabolism?

Answer 9

via the ETC; ubiquinone (coenzyme Q) can produce O2- from O2, which can then for H2O2 or an OH radical; degradation of heme: oxygenase rxn; degradation of purine nucs: hypoxanthine–>xanthine; transport of O2 by RBC

Question 10

How can ROS cause damage in the cell?

Answer 10

Lipid damage–damages cell membrane, ER, golgi etc: increases permeability, ions flow in, cell swells; DNA and protein damage; mitochondria damage; lipid peroxidation

Question 11

Defence mechs against ROS

Answer 11

antioxidants (vit c, e, keratinites, flavonites); Ez defense

Question 12

How is glutathione reduced?

Answer 12

Through glutathione reductase using the NADPH generated from G6PD

Question 13

How does glutathione reduce?

Answer 13

Reduces H2O2 via glutathione peroxidase

Question 14

Symptoms of G6P D deficiency?

Answer 14

hemolytic anemia and jaundice; ROS damage RBC membrane causing lysis; ROS cross-linking of Hb forms insol aggregates–Heinz bodies and cellular proteins (Hb with membrane proteins); high reticulocyte count;

Question 15

treatment

Answer 15

eat food rich in antioxidants; avoid factors that create ROS (oxidant drugs, fava beans, infection)

Question 16

classes of severity

Answer 16

class 1–most severe, <2% normal function; class 4, >60% normal function , no symptoms

Question 17

metabolic consequences of G6PD deficiency

Answer 17

low NADPH; cofactor in synthesis of some biomolecules–>e.g. fatty acids, steroids; cofactors in reduction of oxidized biomolecules such as glutathione;
ROS

Question 18

GSH reduces h peroxide to H2O

Answer 18

ya

Question 19

how do heinz bodies form from ROs?

Answer 19

damage cell membrae and causes cross-linking of released Hb with other Hb or proteins (e.g. membrane proteins)–> creates insoluble aggregates