Enzymes are proteins. Proteins are long chains of aminoacids linked to each other by peptide bonds. Aminoacids have many functional groups in their structure. These functional groups are, many of them at least, ionisable. As they are weak acids and bases in chemical nature, this ionization is influenced by pH of the solution. For many enzymes, activity is influenced by surrounding pH. This is depicted in the curve below, explain briefly.
• Enzymes show highest activity at an optimum pH.
• The dependence of enzyme on pH is due to the presence of charged amino acid at its active site, variation causes changes in charge of amino acid.
• Hence, in both the cases either when the pH is less than the optimum pH or greater than it, enzymetic activity decreases.
• Therefore, we get a bell shaped curve of ezymetic activity against pH.