Question

Are there other ways, besides heat, of controlling enzymatic activity? Give an example.

Answer 1

Changing pH, the presence of co-factors, the choice of buffer, and the availability of substrates can all influence enzymatic activity.

Explanation:

1: pH
For starters, pH is important: tweaking it will have an effect on the reaction rate. You have to be careful though, as a small deviation CAN have a disastrous (and usually irreversible) effect.

2: Co-Factors
A lot of enzymes are inactive by themselves, and need to be "started up" by a co-factor, or co-Enzyme.
This can be a simple ion (`Ca^"++"` and `Mg^"++"` are well-known ones), but also a more complicated molecule (e.g. Co-enzymeA).

3: Buffer
The choice of buffer can also have an influence, though most run-of-the-mill enzymes are fairly happy with standard TRIS/TBE Buffers... (depends on the specific enzyme)

4: "Strangling"

If an enzyme uses more than one substrate, diminishing the amount (read: availability) of one of them will influence reaction rate, though only in the negative sense of course.