what is the lock and key theory???

Question

or if you know any websites which helps explain it

Answer 1

it is where the active site has a gap exactly the size and shape of the substrate that fits it to fulfil it's purpose

this means that the substrate fits perfectly into the active site and it can carry on doing its normal enzyme-y stuff...

doesn't answer for the inhibition thing though, (why enzymes sometimes don't work), if you wanna look into it further look at competetive inhibition/non-competetive inhibition on wikipedia...thats usually good

www.wikipedia.org

hope this helps =)

Answer 2

The lock and key structure in biochemistry is a theory on why enzymes catalyse reactions. This theory states that all enzymes and substrates (the object which the enzyme act on) have specified structures (active site) and chemical properties. The substrate fits into the enzyme's active site, and they react. The substrate is broken down, and then the enzyme can act on the next substrate. This can be done as quickly as 32 million particles per second. The induced fit model is an expansion of this idea.

This means that, only a certain and correctly sized and shaped key can fit into a certain lock, only a certain substrate (key) can fit into a certain active site (or key hole) in the enzyme(lock). This model was replaced with the latthe active site to adapt to the form of the substrate.

Part of this is the idea of competitive inhibition, where an inhibitor competes with the substrate for the active site. Non-competitive inhibition is a form of inhibition, where the inhibitor binds to an allosteric site of an enzyme which is not near the active site. The binding of the inhibitor to the allosteric site results in the alterations in the shape of the enzyme, resulting in a distorted active site that does not function properly.

The binding of a non-competitive inhibitor is usually temporary. Poisons are inhibitors that bind irreversibly. For example, penicillin inhibits an enzyme needed by bacteria to build the cell wall. This causes the bacteria to die quickly and keep them from reproducing.

Answer 3

It means that an enzyme enters a substrate or "active site" in such a way that it's a perfect fit. This is the rather old-fashioned theory explaining how enzymes work. The current, more popular theory is the "hand in glove theory", which states that the enzyme modifies the shape of the substrate to fit in.

Source: My Grade 12 Chem book.

Answer 4

the lock and key theory means that the substrate fits exactly into the active site of the enzyme, and doesnt have to be forced to react, it is all passive.

as for lock and key inhibitors, an active site directed inhibitor is an inhibitor which is the same shape as the substrate, fits into the active site and stops the substrate from attaching so rate of activity decreases and eventually stops.

non-active site directed inhibitors attach to the enzyme somewhere else and they physically change the shape of the active site so that the substrate can no longer bind.

hope this helps.

Answer 5

It is about the enzyme activity. This tells about the specificity of enzymes, which means that ever specific substrate molecule is acted upon by its specific enzyme just like a specific key which operates upon a specific lock.

Answer 6

Enzyme theory... how I loathed thee...

the enzyme molecules are a perfect fit for the active site. Very simple. We now know it's nothing like that tho, activesites mould themselves accordingly. Like a glove to a hand. Thank god too coz otherwise we'd have next to no drugs :S

Answer 7

It's a theory on why enzymes catalyse reactions. This theory states that all enzymes and substrates(the object the enzyme acts on)have specified structures and chemical properties.

Answer 8

havent hear dit b4

Answer 9

http://www.elmhurst.edu/~chm/vchembook/571lockkey.html


http://en.wikipedia.org/wiki/Lock-and-key_model_(enzyme)