Pentose Phosphate Pathway Flashcards
What facilitates the conversion of Glucose-6-P to 6-Phosphogluconolactone?
Glucose-6phosphate dehydrogenase
[NADP+ -> NADPH]
What was released during the conversion of 6-Phosphogluconolactone to 6-phosphogluconate?
H2O was used, releasing H+
What facilitates the conversion of 6-Phosphogluconolactone to 6-phosphogluconate?
Lactonase
What were released during the conversion of 6-Phosphogluconate to ribulose-5-Phosphate?
CO2 (Decarboxylation)
NADP+ –> NADPH
What facilitates the conversion of 6-Phosphogluconate to ribulose-5-Phosphate?
6-phosphogluconate Dehydrogenase
What are the fates of Ribulose-5-Phosphate?
Ribose-5-phosphate via isomerization
Xylulose-5-phosphate via epimerase
What will the fate be when ribulose-5-phosphate is isomerized?
Ribose-5-phosphate
What will the fate be when ribulose-5-phosphate is epimerized?
Xylulose-5-phosphate
Describe what happens in the isomerization of ribulose-5-phosphate to ribose-5-phosphate
Ketone was converted to aldehyde
Differentiate ribulose-5-phosphate and xylulose-5-phosphate
Differ in Chirality
Just Note: xylulose-5-phosphate is a diastereomer
What is an essential component of transketolase?
Thianine pyrophosphate
What does transketolase do?
This transfers 2 carbons from ribose-5-phosphate, leaving Glyceraldehyde 3-phosphate as a product
The 2C will be transferred to xylulose-5-phosphate converting into seduloheptose-7-phosphate
What will be the fate of GA3P of PPP?
- The GA3P can get fed into glycolysis when needed
- Can be involved in Gluconeogenesis when needed
- React with Seduloheptose-7-phosphate
What happens with the reaction of GA3P and Seduloheptose-7-phosphate?
3C of seduloheptose-7-phosphate will be transferred to GA3P resulting to Fructose-6-Phosphate (6C).
While Seduloheptose-7-phosphatase becomes erythrose-4-phosphate (4C).
What facilitates the reaction and conversion of GA3P and seduloheptose-7-phosphate into their products?
Transaldolase
What is the fate of Fructose-6-Phosphate of PPP?
CAN be fed into glycolysis [depending on the body’s need]
What will happen to erythrose-4-phosphate of PPP?
React with xylulose-5-phosphate from epimerization of ribulose-5-phosphate that’s just hanging around.
This will be facilitated by transketolase (TPP).
2C is taken from Xylu-5-P transferred to eryth.
Product: GA3P & Fructose-6-phosphate
Phases of PPP?
Oxidative phase
Non-oxidative phase
What are the oxidative phase of PPP?
Glucose—-> ribose-5-phophate & xylulose-5-phosphate
[step 1-4]
Function of oxidative phase
Make NADPH & Ribose-5-phosphate
Function of non-oxidative phase?
Make ribose-5-phosphate without making NADPH
What is non-oxidative reaction also known as?
Carbon shuffling reactions
