L:27 Phosphate pathway Flashcards
What are the 3 reactions in the oxidative phase that makes NADPH
- Glucose 6-phosphate dehydrogenase
- Lactonase
- 6-Phosphogluconate dehydrogenase
What does Glucose 6-phosphate dehydrogenase do in oxidative phase 1?
Oxidizes G6P to form a lactone*rate limiting
What does Lactonase do?
IS A HYDOLASE and opens the ring by adding water
What does 6-Phosphogluconate dehydrogenase do?
Oxidative decarboxylation of 6-Phosphogluconate to form Ribulose 5-phosphate
reduces NADP+ to form NADPH*
Why do we need NADPH?
Functions as a cofactor for reductase enzymes that catalyze substrate reduction
Helps with synthesis of monomers and reuduction of Glutathione and cytochrome P450
What is Glutathione?
A tripeptide of gamma-Glu, Cys, Gly
What does Glutathione do?
Inactivation of peroxides from GSHGSSG
regeneration of oxidized (GSSG) to Reduced (GSH) uses what?
NADPH
Ratio of GSH:GSSG in healthy cells with plenty of NADPH is?
~500:1
What happens if NADPH is under-produced?
Glucose-6-phosphate dehydrogenase deficiency (G6PDD)
Most common genetic disease, x-linked recessive
Most severe effect G6PD?
blood is normal but liver cannot conjugate bilirubin
If bilirubin enters brain can cause deafness, cerebral palsy, or death
3 structures of G6PD and their activity?
Monomer-inactive
Dimer-active
Tetramer-active
Can G6PD cause ataxia telangiectasia?
Yes
Activators of G6PD regulator
- Dimerization
- Transcription factor for antioxident gene
- Cell cycle and synthesis activators
- Insulin
Inhibitors of G6PD
Phosphorylation
Apoptosis-signaling proteins
