Active/Binding Sites

[Drunk]

Hey guys
Quick/maybe stupid question;
The active site is the part of an enzyme where the substrates bind to, right?
So what the hell is the binding site? Is it part of the enzyme or the substrate? Or is it part of both?

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Do non-competitive inhibitors just stay in between the substrate and the enzyme, or do they like, actually bind to the substrate seeing as they don't bind to the active site?

[vexx]

Hey guys
Quick/maybe stupid question;
The active site is the part of an enzyme where the substrates bind to, right?
So what the hell is the binding site? Is it part of the enzyme or the substrate? Or is it part of both?

yeah the enzyme has the active site where the substrate binds to. the binding site is basically where the chemical bonds form between them, so it occurs at the active site when the substrate-enzyme complex is formed.

[Drunk]

Right, so non-competitive inhibitors can get into this binding site? Do they just stay in between the substrate and the enzyme, or do they like, actually bind to the substrate seeing as they don't bind to the active site?

[WhoTookMyUsername]

the binding site is the active site. well to be exact, the binding site is the site of binding when it is bound...

i think...

[HERculina]

omg i was also confused over active/binding sites too the other day!
my txtbook says that ' some enzymes can have two or more active binding site'
can someone please elaborate on this

[WhoTookMyUsername]

that is true. An enzyme can have 2 or more binding sites. You do not need to know anything more than that (even don't need to know has 2 

[HERculina]

out of interest, does this mean more than two substrates can fit into two separate active sites on one single enzyme? or is this notion totally wrong?
or is the other binding site only for inhibitors

[Drunk]

yeah i have no clue how non-competitive inhibitors even work now
i know that they can bind to other parts of an enzyme to change its shape, but im pretty sure it can do something at the binding site, or do something to screw up the substrate, but im not sure what

[HERculina]

hmmmmm. u noe wen a non-competitive inhibitor changes its shape -does it change the active site's shape specifically or just the enzyme as a whole :/
and if its the active site, wouldnt this be denaturing? why is it sometimes reversible?

[Drunk]

non-competitive inhibitors change the active site's shape and im pretty sure non-competitive inhibition is irreversible - its the competitive ones that are reversible by increasing the substrate concentration

[Truck]

Non-competitive inhibitors attach themselves to some point on the enzyme that isn't the active site, which affects the structure of the enzyme and thus the way the enzyme works - stopping them from functioning properly.

[HERculina]

non-competitive inhibitors change the active site's shape and im pretty sure non-competitive inhibition is irreversible - its the competitive ones that are reversible by increasing the substrate concentration

isnt it that both can be irreversible and reversible?

IM SO CONFUSED. O.O
will the enzyme sac have anything to do with inhibitors anyway?

[jasoN-]

non-competitive inhibitors change the active site's shape and im pretty sure non-competitive inhibition is irreversible - its the competitive ones that are reversible by increasing the substrate concentration

this is correct.
competitive inhibition is reversible by adding large amounts of substrate that eventually will literally 'knock off' the competitive inhibitor.

non-competitive inhibitors attach onto another region of the enzyme, changing the active site of the enzyme.
they however can be both reversible or non-reversible depending on the inhibitors interaction.
Reversible: if the interaction between the enzyme and the non-competitive inhibitor is WEAK, after a finite period it may dissociate from the enzyme, also other molecules are able to bump off and break the weak interactions between the enzyme and the inhibitor.
Irreversible: if the inhibitor combines or destroys the functional group(s) on an enzyme, it may form covalent bonds. This changes the shape of the enzyme and is now regarded as non-functional.
The only way the system overcomes this is producing more of the enzymes to compensate the lack of production of the product (made from substrate-enzyme complex)