Uncompetitive Inhibition

[dmission]

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Does anyone know if uncompetitive inhibition is on the MCAT? The book I'm using goes over, in detail, competitive, noncompetitive, and irreversible, but uncompetitive isn't mentioned at all.

 

[MShopes]

Does anyone know if uncompetitive inhibition is on the MCAT? The book I'm using goes over, in detail, competitive, noncompetitive, and irreversible, but uncompetitive isn't mentioned at all.

I thought noncompetetive would be same as uncompetitive...however I'm using EK and have only seen non-competitive, irreversible, and competitive inhibitors just like you.

 

[stsa84]

Does anyone know if uncompetitive inhibition is on the MCAT? The book I'm using goes over, in detail, competitive, noncompetitive, and irreversible, but uncompetitive isn't mentioned at all.

Lol, what? I had never heard of uncompetitive inhibition until I googled it and read the Wiki on it. Nope, not on the MCAT.

 

[salim271]

I dont know if it does, but just remember that noncompetitive binds to an allosteric site and blocks the active site so E + S doesnt form ES (Enzyme + Substrate), in comparison uncompetitive binds to the joined E and S and forms an ESI complex, I being the inhibitor which stops the substrate from becoming the product.

 

[Axon hillock]

Uncompetitive inhibition will most likely not be on the MCAT. If it is then it will be explained in a passage. In general I haven't seen many questions regarding enzyme kinetics.

 

[imapremed]

http://www.mymcat.com/wiki/Enzyme_Inhibition#Uncompetitive_Inhibition

explains it all! helped me a lot

your welcome!

 

[PingPongPro]

The MCAT books I've seen (EK, TPR) have it wrong. They use the word NONCOMPETITIVE inhibition when explaining UNCOMPETITIVE inhibition. One would assume that these are the same things, but in my biochem class I learned that they are different. I'll try to clarify it to the way I know it, and believe to be true.

Competitive inhibition- inhibitor binds to same site as substrate. Can be overcome with enough substrate concentration.

Uncompetitive inhibition - Inhibitor binds only once substrate has bound to enzyme. Only binds to enzyme-substrate complex. Cannot ever be overcome.

Noncompetitive Inhibition - Special case of mixed inhibition where uncompetitive characteristics = competitive characteristics. I don't think MCAT really stresses these fine details, but its useful to know that they exist.

The books make it confusing by interchangeably using Noncompetitive and Uncompetitive inhibition, but they are not the same thing. You can usually tell what they are referring to by the context.

 

[MShopes]

The MCAT books I've seen (EK, TPR) have it wrong. They use the word NONCOMPETITIVE inhibition when explaining UNCOMPETITIVE inhibition. One would assume that these are the same things, but in my biochem class I learned that they are different. I'll try to clarify it to the way I know it, and believe to be true.

Competitive inhibition- inhibitor binds to same site as substrate. Can be overcome with enough substrate concentration.

Uncompetitive inhibition - Inhibitor binds only once substrate has bound to enzyme. Only binds to enzyme-substrate complex. Cannot ever be overcome.

Noncompetitive Inhibition - Special case of mixed inhibition where uncompetitive characteristics = competitive characteristics. I don't think MCAT really stresses these fine details, but its useful to know that they exist.

The books make it confusing by interchangeably using Noncompetitive and Uncompetitive inhibition, but they are not the same thing. You can usually tell what they are referring to by the context.

I disagree about uncompetitive inhibition. Inhibitor binds as readily to an enzyme with substrate binded as an enzyme alone that don't have substrate... so they can bind when substrate is not added but yet I agree that they can not be overcome.

 

[PingPongPro]

Don't really want to argue over forum about this minute detail, but you are wrong, or learned from an incorrect source.

http://en.wikipedia.org/wiki/Uncompetitive_inhibition

You are also probably confusing noncompetitive inhibition.

 

[MShopes]

Don't really want to argue over forum about this minute detail, but you are wrong, or learned from an incorrect source.

http://en.wikipedia.org/wiki/Uncompetitive_inhibition

You are also probably confusing noncompetitive inhibition.

I'm talking about non-competitive inhibition. You said that EK confuses Uncompetitive with non-competitive...well I just stressed whatever EK said regarding non-competitive inhibition or as you saying, it should be uncompetitive. In short, I'm saying what EK said regarding uncompetitive or non-competitive whichever it is.

And then according to your link, I can say that the difference between uncompetitive and non-competitive then is that non-competitive can bind to enzyme when substrate is there or when it is not there. But uncompetitive bind only when substrate is there. And both bind to area other than the active site. That seems to make more sense.