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Old 08-22-2012
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Arrow Belindalimm Daily Questions: Biochemistry #2

At autopsy of a 28-year-old man, the left ventricle of the heart shows classic contraction band necrosis of the myocardium. Cocaine and it's metabolizes are detected in body fluids. Activity of which of the following enzymes was most likely increased in the patient's myocaridial cells prior to his death?

A. Phosphoenolpyruvate carboxykinase
B. Phosphofructokinase-1
C. Pyruvate dehydrogenase
D. Succinate dehydrogenase
E. Transketolase
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Old 08-22-2012
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I think A
Don't know why
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Old 08-22-2012
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It's B (glycolytic enzyme)
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It's B (glycolytic enzyme)
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Old 08-22-2012
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Myocardium and Cocaine
Answer is B.


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Old 08-22-2012
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Default my answer

B. Phosphofructokinase-1

I've learned from my mistake
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Old 08-23-2012
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Post Answer is B.

Yup. Aerobic metabolism switched to anaerobic one, so emphasizing on glycolysis. Thus, phosphofructokinase-1 is the correct answer.
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Old 08-23-2012
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Unhappy New uncertainty comes.

But I've got another inquiry about the question when thinking further. I thought private dehydrogenase is still a possible choice since acetyl-CoA is decreasing due to anaerobic metabolism. Acetyl-CoA inhibits private dehydrogenase, so when it's inhibitor is gone its activity should be relatively increased.

I'm not sure if it is right or reasonable for me to think in this way. Welcome all of your comments and correction! Thanks a lot!
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Old 08-23-2012
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Quote:
Originally Posted by belindalimm View Post
But I've got another inquiry about the question when thinking further. I thought private dehydrogenase is still a possible choice since acetyl-CoA is decreasing due to anaerobic metabolism. Acetyl-CoA inhibits private dehydrogenase, so when it's inhibitor is gone its activity should be relatively increased.

I'm not sure if it is right or reasonable for me to think in this way. Welcome all of your comments and correction! Thanks a lot!

Well am not exactly sure cause i have done biochem few months ago, but what i think happens in such a situation is, TCA is shut down , that means what ever acetyl coa is being produced its not being used , so it should back up and inhibit pyruvate dehydrogenase , thus increassing pyruvate concentration and pushing it into becoming lactate.. glycolysis runs overtime to produce more n more pyruvate..
please correct me if i am wrong
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Old 08-23-2012
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Quote:
Originally Posted by dr.nitowl View Post
Well am not exactly sure cause i have done biochem few months ago, but what i think happens in such a situation is, TCA is shut down , that means what ever acetyl coa is being produced its not being used , so it should back up and inhibit pyruvate dehydrogenase , thus increassing pyruvate concentration and pushing it into becoming lactate.. glycolysis runs overtime to produce more n more pyruvate..
please correct me if i am wrong
Thanks for your explanation! It makes sense. Sometimes I just find there could be several ways of thinkings, which are all making sense, to one single question or situation, and it is difficult to choose among them to tell which ones are wrong, which one is right or just to tell which one is better over others. This experience most likely takes place in biochemistry since there are so many pathways and then further cross link with each other. Do you have the same feeling?
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Old 08-24-2012
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Quote:
Originally Posted by belindalimm View Post
Thanks for your explanation! It makes sense. Sometimes I just find there could be several ways of thinkings, which are all making sense, to one single question or situation, and it is difficult to choose among them to tell which ones are wrong, which one is right or just to tell which one is better over others. This experience most likely takes place in biochemistry since there are so many pathways and then further cross link with each other. Do you have the same feeling?
Yeah thats true.. Unlike in other subjects where if we know the annswer we could mark it and move on , in biochem we need to cross check every option carefully and finally leaves us confused between 2 options.. but its da same with everyone so dont worry ..
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