[miss_h]

::)
Hi can anyone help me to explain the lock and key mechanism of enzyme function. I also need to look at factors such as build up of toxins in the body, body temp or ph balance.
Would be grateful for any help, thanks. Miss h

[nishant_yagnick]

The lock and key mechanism of enzyme function is like this... the substrate as well as the enzyme both have specific structures.the substrate the fits into the same structure as the enzyme(wish I could give you a diag for understanding).they then in the attatched stage form the enzyme substrate complex.this undergoes a change, when the structure of substrate changes it can no longer "fit" into the grooves and structure of the enzyme, and hence detatches. The enzyme remains uncahnged.hence the enzymehas performed its function.its called lock and key because that's a metaphor for the substrate fitting into the enzyme like a lock and a key.(this was given by fischer)... altough, certain changes have been made in this theory. I suggest you look up the "induced fit" hypothesis as well.
Toxins have a number of effects to inhibit enzymes... which are classified as competitive and non competitive... in short, either they compete with the substrate for the grooves of the enzymes, thereby reducing substrate breakdowm, or they attach to other points in the enzymes and inhibit the change of substrate, even if it does fit the enzyme... high temp(usually 60 degrees+) denature enzymes, low temp, render them inactive. PH changes can also have similar effects, depending on enzyme strucutre... usualy very high or low pH denatures enzymes..

[sovaira]

Something in few words would be that it is all the game of complementarity


If good molecules have got complementarity with the good subtrates they will bind for sure and give positive and desired results.

If the badones have got complementarity with these enzymes then of course they will bind and produce undesired effects , for example disease and alergies.
Well secondary products of these reactions do play an important role too.