Inhibitors??

[saheh]

Hey guys
I'm on my phone because my net is playing up, so this is gunna be a little dodgy.
Anyway, I was just listening to Douchy's podcast on enzymes (in prep for our sac tomorrow) and one thing came up that confused me.

It was about competitive and non competitive inhibitors, which I though I understood, until he said:
A competitive inhibitor can be removed by increase in substrate
And then somethig along the lines that non-competitive can't, and therefore can be more destructive..
 

I always though competitive inhibitors were the bad guys :p
But it makes sense that poisons could bind non-competitively (if you get that haha)

Ok thanks guys I just wanted to clear this up!

Stay cool 

[Shenz0r]

Non-competitive inhibitors bind permanently onto an enzyme's active site. Even if the substrate concentration increases, it cannot bind onto the active site as the non-competitive inhibitor cannot be removed. Hence, your enzymes wouldn't catalyse any more reactions and if that happens you get extremely sick.

[jasoN-]

Competitive inhibitors COMPETE with substrate molecules by forming weak reversible interactions with the enzyme at its active site.
By increasing the substrate concentration, competitive inhibitors may be DISPLACED, and the reaction is favoured to proceed normally.

Non-competitive inhibitors bind onto a DIFFERENT binding site of an enzyme. Once bound, the activity of the enzyme is reduced, or even ceased, most likely due to a change in the tertiary structure.
Non-competitive inhibitors can be either reversible or irreversible, really depends on which inhibitor and the binding groups of the enzyme etc.

[saheh]

Ok thanks guys!
That's much easier to understand now!

Have a good night

[LOLs99]

Good luck with your 2nd sac.

[Russ]

Non-competitive inhibitors bind permanently onto an enzyme's active site. Even if the substrate concentration increases, it cannot bind onto the active site as the non-competitive inhibitor cannot be removed. Hence, your enzymes wouldn't catalyse any more reactions and if that happens you get extremely sick.

Woah, be careful with this. Non competitive inhibitors absolutely do not bind the active site, it's why they're called non-competitive. They also don't have to bind permanently, they can be transient.

[saheh]

Non-competitive inhibitors bind permanently onto an enzyme's active site. Even if the substrate concentration increases, it cannot bind onto the active site as the non-competitive inhibitor cannot be removed. Hence, your enzymes wouldn't catalyse any more reactions and if that happens you get extremely sick.

Woah, be careful with this. Non competitive inhibitors absolutely do not bind the active site, it's why they're called non-competitive. They also don't have to bind permanently, they can be transient.

i thought so..
what about JasoNs answer?
it sounds more accurate...

[Wazzup]

Reversible Inhibitors
•   Competitive Inhibition: Inhibitor molecule blocks the active site, preventing use.
•   Non-Competitive Inhibition: Inhibitor molecule binds elsewhere and slows the reaction rate.
•   Allosteric Inhibitor: Inhibitor binds elsewhere and distorts the active site, preventing use.

Irreversible Inhibitors (Poisons)
•   Inhibitors which bind permanently to the active sites of enzymes.
•   Many are heavy metals.

[InsaneMcFries]

Reversible Inhibitors
•   Competitive Inhibition: Inhibitor molecule blocks the active site, preventing use.
•   Non-Competitive Inhibition: Inhibitor molecule binds elsewhere and slows the reaction rate.
•   Allosteric Inhibitor: Inhibitor binds elsewhere and distorts the active site, preventing use.

Irreversible Inhibitors (Poisons)
•   Inhibitors which bind permanently to the active sites of enzymes.
•   Many are heavy metals.

I don't think that much detail is required.

Basic idea is that competitive inhibitors compete with the substrates by matching their shape and binding to the active site of the enzyme, but cannot be broken down and therefore stop the enzyme from continuing to react. An increase in substrate concentration would result in a higher ratio of substrates vs inhibitors and thus the rate of reaction will still increase.
Non-competitive inhibitors will bind to another area of the enzyme and distort the shape of the enzyme's active site, meaning that substrates cannot bind with the new shape. These inhibitors are mostly irreversible, as the shape of the protein is unlikely to regain its original shape.

[Thelimz]

The competitive inhibitor bond covalently to the active site of an enzyme, which does not let substrates bond to this site anymore, this reaction is irreversible. Non-competitive inhibitors bond to a different place on the enzyme, ie not the active site, non-covalently meaning that the reaction is reversible but it affects the rate of reaction of the enzyme with the substrate.

[golden]

To be honest there are so many different situations possible. Because it's a competitive doesn't mean it's super bad but it can be. Because it's non-competitive doesn't mean it's good but it can be.