AAMC 11 Catalyst

[MedPR]

So the passage says that cP-450 is a catalyst in the metabolism of toxins. The passage also says normally cP-450 can metabolize barbituates, but that alcohol is a competitive inhibitor of "barbituate metabolism"

As you can see, I ruled out the other two choices and was stuck between the correct answer and the answer I picked. I initially picked B, but then thought about it and came to the conclusion that the binding of a substrate to a catalyst is what gets inhibited, not the catalyst itself.

I picked denature because the passage also states that cP-450 is an Iron core with 3Nitrogens on it and I figured that the alcohol would disrupt the tertiary structure of the cP-450 by hydrogen bonding with the nitrogens.

Am I missing something here, or are the answers worded poorly?

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[MedPR]

Ah damn, just realized I put both of these questions in the wrong forum.

Can a mod kindly just move them rather than close them? Thanks!

 

[MedPR]

bump

 

[HollowSuperet36]

If I remember correctly the passage stated that alcohol was a competitive inhibitor of this enzyme, thus giving us the answer.

 

[MedPR]

If I remember correctly the passage stated that alcohol was a competitive inhibitor of this enzyme, thus giving us the answer.

The passage states that alcohol is a competitive inhibitor of barbituate metabolism.

The enzyme doesn't get competitively inhibited, the binding of the substrate (barbituate) is what gets competitively inhibited. If the enzyme metabolizes both alcohol and barbituate, alcohol does not inhibit the enzyme, it just inhibits barbituate metabolism. The enzyme is still functioning, just in a different process/reaction.

 

[mcloaf]

The passage states that alcohol is a competitive inhibitor of barbituate metabolism.

The enzyme doesn't get competitively inhibited, the binding of the substrate (barbituate) is what gets competitively inhibited. If the enzyme metabolizes both alcohol and barbituate, alcohol does not inhibit the enzyme, it just inhibits barbituate metabolism. The enzyme is still functioning, just in a different process/reaction.

But for the purposes of the reaction in the question, alcohol IS inhibiting the reaction. It doesn't matter that the enzyme is doing something else, its actions on barbiturates is being inhibited by the alcohol.

 

[MedPR]

But for the purposes of the reaction in the question, alcohol IS inhibiting the reaction. It doesn't matter that the enzyme is doing something else, its actions on barbiturates is being inhibited by the alcohol.

Yea I understand why. I had initially marked "inhibiting" but then decided it was a trap. I have to start trusting that I know of all the traps and won't fall for them instead of contsantly looking for them!

 

[km17]

Yea I understand why. I had initially marked "inhibiting" but then decided it was a trap. I have to start trusting that I know of all the traps and won't fall for them instead of contsantly looking for them!

If you feel a trap coming on, I find it helpful to look for another word in either the question or the responses that might give me a clue...

For example: the word in the response choice that you chose used "denature" but you thought about it as "disrupt". While an alcohol could potentially hydrogen bond with the enzyme (and probably does in the active site to competitively block the barbituate!), alcohol is not a common denaturing agent for proteins...that's usually heat or changes in acidity! Voila, tricky response choice busted!

 

[MedPR]

If you feel a trap coming on, I find it helpful to look for another word in either the question or the responses that might give me a clue...

For example: the word in the response choice that you chose used "denature" but you thought about it as "disrupt". While an alcohol could potentially hydrogen bond with the enzyme (and probably does in the active site to competitively block the barbituate!), alcohol is not a common denaturing agent for proteins...that's usually heat or changes in acidity! Voila, tricky response choice busted!

Thanks for that! That's a great thing to keep in mind. Trying to soak up last bits of knowledge before my test tomorrow Didn't study at all today or after 5pm last night.

 

[km17]

My test is tomorrow too Good luck!

 

[km17]

And just to clarify, I meant alcohol is not a common denaturing agent for proteins in the human body...obviously when a nurse swabs your arm with an alcohol pad before an injection, they are doing it to denature bacterial proteins! (In case we see a question like this tomorrow!)

 

[MedPR]

My test is tomorrow too Good luck!

And just to clarify, I meant alcohol is not a common denaturing agent for proteins in the human body...obviously when a nurse swabs your arm with an alcohol pad before an injection, they are doing it to denature bacterial proteins! (In case we see a question like this tomorrow!)

Thanks for adding that. Good luck to you too!