Hey all!!Welcome back to my Biochemistry blog, continuing on the topic Glycolysis, today we will be moving on to looking at what happens after glycolysis in the fates of pyruvate. Let’s get right into it!
Pyruvate has three fates, one that occur under aerobic conditions and two occurring under anaerobic conditions. See below image showing these three different fates of pyruvate.
UNDER AEROBIC CONDITIONS
1. ENTRY INTO THE TCA CYCLE
v Oxidative decarboxylation reaction
v Reaction goes in one direction only
v Oxygen is present
v Link reaction- links pyruvate to TCA cycle
v Enzyme- Pyruvate dehydrogenase
v Coenzymes/Cofactors- CoA-SH, NAD+, TPP, Lipoate, FAD
UNDER ANAEROBIC CONDITIONS
2. CONVERSION TO LACTATE
v Occurs in the Erythrocyte (mature red blood cell)
v Depends solely on glycolysis to get energy
v No mitochondria present so pyruvate cannot be converted to Acetyl-CoA instead is converted to lactate
v In the cell there is a limited amount of NAD+ present, so for glycolysis to continue more NAD+ needs to be made, this is particularly important for the erythrocytes because they rely on energy from glycolysis.
v No ATP is produced here
v The purpose of fermentation is the regeneration of NAD+ for glycolysis to continue
v Erythrocyte gets 2 ATP molecules from every glucose molecule that enters glycolysis
v Enzyme- Lactate dehydrogenase
3. ETHANOL FERMENTATION
v Regeneration of NAD+ for glycolysis to continue
v Enzyme- Pyruvate decarboxylase & Alcohol dehydrogenase
Fermentation in our everyday lives
v Beer brewing
v Wine making
v Taste of sour milk
v Producing biofuels
v The characteristic taste and fragrance of sauerkraut
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