Enzymes

[CrazCo]

You know how varying pH levels can affect the reaction rate of enzymes. Why is this from a molecular standpoint. Do they ions from the enzyme get attracted to the acidic/basic environments and leave the enzyme?

[dr.syntax]

You know how varying pH levels can affect the reaction rate of enzymes. Why is this from a molecular standpoint. Do they ions from the enzyme get attracted to the acidic/basic environments and leave the enzyme?

 

REPLY: There are a very many different enzymes evolved to do a wide variety of tasks. The making or breaking of chemical bonds of many different types. It`s from the" molecular standpoint" because each of these different enzymes are designed,shaped to deal with a specific molecule. The PH value`s effect on any specific enzyme would depend on wich enzyme it is. As far as I know most of what is produced by enzymes are not ions though some may very well be, that part I don`t know off hand and can`t answer. Why not do a google search such as : do some enzymes produce ions ? You`ll probably learn a lot about enzymes in general. Here is a good website to learn about enzymes at : http://en.wikipedia.org/wiki/Enzyme . ...Dr.Syntax

Edited October 4, 2009 by dr.syntax

[insane_alien]

pH changes will denature an enzyme.

 

they depend on hydrogen bonding for their secondary structure which also depends on the solution the enzyme is in. changing the pH will cause the balance to change which will affect tertiary and secondary structure and cause the active sites of the enzyme ot nolonger be effective.

[Mr Skeptic]

Or rather, change from the ideal pH value. Enzymes are usually specialized for a particular pH range.

[insane_alien]

well if you want to be pedantic.

[dr.syntax]

pH changes will denature an enzyme.

 

they depend on hydrogen bonding for their secondary structure which also depends on the solution the enzyme is in. changing the pH will cause the balance to change which will affect tertiary and secondary structure and cause the active sites of the enzyme ot nolonger be effective.

 

REPLY: You are wrong about this. Of course with a strong enough PH change this would be true for most enzymes. But many enzymes depend on changing PH values as a way of regulating them. For an thorough explanation of this with graphs and such go to : http://plantphys.info/plant_physiology/enzymekinetics.shtml . Scroll down about halfway or more to the section titled: Enzyme conformation is altered by PH change. ...Dr.Syntax

[insane_alien]

yes, it changes the activity of the enzyme be denaturing the enzyme.

 

just like i said.

[dr.syntax]

I misinterpreted your meaning. MEA CULPA ...Dr.Syntax

[CrazCo]

But how does it denature? It just breaks the hydrogen bonds? Or is it the ionic bonds?

[CharonY]

Ionic interaction in the broadest sense. pH changes lead to protonation or deprotonation of reactive groups. These can change the the interaction of the amino acids within the proteins and hence the overall structure. It does not necessarily need to denaturation (i.e. loss of secondary and tertiary structure), but it may lead to a conformation that is less active than the optimal one.

In other words, the optimal pH of an enzyme is when the charge load of the protein results in the stabilization of the structure with the optimal activity.