ANOTHER enzyme question?

Question

hey guys, can someone shed some light on this, i've tried doing research but havn't come up with the answer:

cite two characteristic features (with explanation) of the active site of an enzyme

Thankuu..xxx

Answer 1

You have asked question about the active site of the enzyme, not about the whole enzyme.
So, the answer would be the following:
Active sites have a specific geometry wherein there is a catalytic group to catalyze the reaction.
According to Koshland's induced-fit theory the geometry of the active site is different when substrates are not present. In this case the enzyme is in a thermodynamically stable state but in a catalytically unfavorable state.
The presence of substrate induces the enzyme to undergo a change whereby the geometry of the active site changes to a configuration which is catalytically favorable but thermodynamically unstable. This flip-flop change is the characteristic of the active site.
This is in addition to the allosteric change it undergoes in the presence or absence of the coenzyme or cofactor.

Answer 2

Enzymes are proteins that speed up chemical reactions. Without enzymes, most chemical reactions would still occur, but they would happen much too slowly to sustain life. Because the body is essentially a "chemical processing plant," enzymes are crucial in every aspect of physiology. All enzymes have certain characteristics in common, which enable them to be effective. To illustrate these features, a fixed-size wrench is a useful metaphor.
First, enzymes are highly specific. Like a wrench that will only fit a 5/16-inch bolt, each enzyme generally works with only a particular kind of molecule.

Second, enzymes can speed up the same chemical reaction going in opposite directions. A wrench can either take things apart or put them together, depending on whether we begin with the parts already assembled or not. Similarly, an enzyme may ordinarily break a molecule into two pieces, but will put it back together again if it is provided only with the pieces.

Third, enzymes are unaffected by the reactions that they speed up. Just as a wrench remains the same after it has unscrewed thousands of bolts, so does an enzyme keep working for us after it completes a chemical reaction. This characteristic greatly increases the efficiency of enzymes, because they can be reused over and over again.

ANY GOOD?

Answer 3

This one is alot easier than the last one -goes to get advanced biology book- goodness i still have these!

1Active site is a 3-dimensional entity! i'm guessing ur smart enough to know what that means right its not 2D! its not flat!

2Specificity. Active site provides specificity for its particular substrate, which is a characteristic feature of enzymes. Fischer proposed in 1890 that substrate & enzyme behaved like key in lock i.e. substrate had a matching shape to fit into the active site.

Answer 4

The active site of an enzyme contains two main features: a binding site and a catalytic site. The binding site is generally small and consists of amino acids so that it will bind only to specific substrates. The catalytic site of the enzyme then interacts with the substrate, often using co-factors, to catalyze the reaction.

Answer 5

The enzymes are very selective from material, temp., medium, pH points of view. Thus maltase acts only on maltose, not on lactose ! beta glycosidases attack only beta sugar linkages, in their optimum conditions ! Protein enzymes are equally selective - they ignore sugars . But enzymes contain several bonds, including sugar & peptide links. They may get affected by other suitably acing enzymes. But our bio systems are so unique that they are very effectively isolated. Also the pH & other factors decides the final reactions & products . This Q is quite thought provoking : imagine your dream enzyme starts splitting a maltase, & that maltase has ability to attack lipase under identical conditions ! - it can complicate the set up, thank God , Nature avoids this !

Answer 6

unique to substrate forming the substrate enymebond
and are sensitive to ph temperature and substrate concentration
which determines their activity