Question

Discuss four factors that influence enzyme activity (20 marks)

Answer 1

Enzymes are biocatalyst substance which are made up of proteins or RNA ( ribozyme ) . They may or may not have a co factor , a substance other than protein which may be organic ( NAD, FAD ) or elements ( like Iron, Copper ).

Enzyme activity is the amount of enzymes that can convert 1 micromol of substrate to product in a minute under optimal condition.

Enzyme activity can be influenced by :

1. Temperature : an enzyme have an optimum temperature, temperature where an enzyme have the most enzymatic activity. Different enzymes have different optimum temperature. But as we deviates from the optimum temperature ( higher or lower than the optimum temperature ) the enzyme activity will decrease. But if the temperature keeps on increasing the enzyme may be denatured and cannot use again. But as we keep decreasing the temperature say frozen sate, the enzyme will not show any activity but might show the activity if we bring to the optimum temperature but with little less activity.

2. pH : like temperature an enzyme have its own optimum pH where the enzyme works best. As we deviates from the optimum pH the enzyme activity will decrease.

3. Enzyme and substrate concentration : oviously, enzyme activity will increase if there is increase in enzyme and substrate concentration.  But a point will come where there is no longer increase in enzyme activity , this point is called saturation point. From this point if u keep increasing either substrate or enzyme ( not both) there will be no increase in enzyme activity.

4. Inhibitors : inhibitors are molecules that inhibits or decrease the activity of an enzyme. So, if there is large amount of inhibitors then the enzyme activity will decrease .

Most common example of enzyme inhibitor is Cyanide, which irreversibly inhibits an enzyme cytochrome C oxidase in mitochindria in electron transport chain.