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Enzymes: Selective vs. Competitive Inhibition.

Hi guys,
I was wondering if I could get some help with differentiating between selective and competitive inhibition of enzymes.
I know competitive inhibition is when a molecule competes with the substrate for the active site of the enzyme, but I can't get around what selective inhibition is.
thanks :smile:
Reply 1
Original post by jungykang
Hi guys,
I was wondering if I could get some help with differentiating between selective and competitive inhibition of enzymes.
I know competitive inhibition is when a molecule competes with the substrate for the active site of the enzyme, but I can't get around what selective inhibition is.
thanks :smile:


I'm not 100% sure, but I think of it as selective meaning specific, it only chooses the enzyme that it can bind with, ones with a specific complementary shape to fit in the active site, but can't/doesn't react with the enzyme, so not catabolic or anabolic reaction occurs.

maybe have a read of this?
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC392972/pdf/pnas00021-0167.pdf
(edited 9 years ago)
Reply 2
Original post by jadys10
I'm not 100% sure, but I think of it as selective meaning specific, it only chooses the enzyme that it can bind with, ones with a specific complementary shape to fit in the active site, but can't/doesn't react with the enzyme, so not catabolic or anabolic reaction occurs.

maybe have a read of this?
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC392972/pdf/pnas00021-0167.pdf

I'll definitely give it a read! Thanks.
But what you have described is competitive inhibition (in the sense that you need a specific shape similar to the substrate)
Hey, jungykang!

I think I'm on a different exam board to you, as we learnt about competitive and non-competitive (i.e. selective) inhibition. Regardless, the content is likely more or less the same.

As you already know competitive inhibition is where a different molecule outcompetes a potential substrate for an enzyme's active site, effectively blocking it. The competitor must also be complementary in shape to an enzyme's active site to bind, but not necessarily in a manner identical to the intended substrate's. This kind of inhibition is usually reversible.

Selective inhibition is slightly different. A selective inhibitor will attach to a part of an enzyme that isn't it's active site in order to modify the active site's shape. This kind of inhibition is more permanent than competitive, but it can still be undone.



Above is a picture from my exam board's text book detailing selective inhibition. Hope this post helps!

Yours,
Grey
(edited 9 years ago)
Reply 4
Original post by ThenameisGrey
Hey, jungykang!

I think I'm on a different exam board to you, as we learnt about competitive and non-competitive (i.e. selective) inhibition. Regardless, the content is likely more or less the same.

As you already know competitive inhibition is where a different molecule outcompetes a potential substrate for an enzyme's active site, effectively blocking it. The competitor must also be complementary in shape to an enzyme's active site to bind, but not necessarily in a manner identical to the intended substrate's. This kind of inhibition is usually reversible.

Selective inhibition is slightly different. A selective inhibitor will attach to a part of an enzyme that isn't it's active site in order to modify the active site's shape. This kind of inhibition is more permanent than competitive, but it can still be done.



Above is a picture from my exam board's text book detailing selective inhibition. Hope this post helps!

Yours,
Grey

Ahhh Brilliant! Thank you so much!! I take the IB and for me that "selective inhibition" process is just non-competitive inhibition in the textbook for us. Maybe its just a difference in terminology? Anyways- Thank you, this got my confusions cleared up :smile:

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