the biochemGazettE: Fate of Pyruvate!!!!!

ballgob-fig20_017

Well it should be more the Fates of Pyruvate, but whatever. So as we can see from the lovely little pic above there three ways pyruvate can go…

1. Converted into Acteyl-CoA and enter Krebs Cycle, a AEROBIC process.

2. Converted into Lactate which happens in organisms ie. us, a ANAEROBIC process.

3. Converted into Ethanol the good stuff…NEVER! It’s bad for you! A ANAEROBIC process in microorganisms.

1. Acetyl-CoA path, here 3c pyruvate is converted to 2C Acetyly-CoA which is the molecule used in the krebs cycle. The enzyme that does this is Pyruvate dehydrogenase complex and remembering that anything with dehydrogenase in the name NADH is formed and yes it is along with one CO2. Pyruvate Dehydrogenase is a complex thus it has buddies helping him, well cofactors which are

a. TTP (thiamine pyrophosphate)

b. NAD+

c. FAD

d. Lipoate

e. Coenzyme A

Pyruvate oxidation

2. Pyruvate to Lactate, this happens to all of us when we do strenuous activities were you get cramps in your muscles and soreness. This reaction is important because it gives back NAD+ which is vital for Glycolysis to proceed, as it is used in step 6. The enzyme at work here is Lactate dehydrogenase, it adds a water molecule across the C=O in the pyruvate to give the lactate/ lactic acid. These reactions are also seen in Erythrocytes our red blood cells and jus a lil reminder it is a anaerobic process. ie. no oxygen is present.

Pyruvate_to_lactate 3. Finally the last path pyruvate can go is to Ethanol by fermentation, another anaerobic process but occurs in microorganisms. There are two enzymes at work here:

a. Pyruvate decarboxylase- this enzyme requires TTP  coenzyme and Mg2+ cofactor to work it removes a carbon atom

(decarboxylates) from the pyruvate and forms Acetaldehyde.

b. Alcohol Dehydrogenase- another dehydrogenase, but we get NAD+ instead of NADH, thus why this reaction is another form of

gaining back NAD+ and finally Ethanol is formed.

Pyruvate_decarb_1So there it is folks Fate of Pyruvate, hope it was as helpful!:D

References:

afoggyone.tripod. “Fates of Pyruvate”.http://afoggyone.tripod.com/pyruvate1.html

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