Why the enzyme reaction rate decreases upon decreasing and increasing the pH of the enzyme’s environment from the optimum pH?

A Study on the Effects of pH on Enzyme Reactions Rate

The enzymes are essential proteins for living and responsible for many biochemical reactions. The pH environment can affect enzyme reactions and cause them to be more sensitive than others. A pH value that is optimal for an enzyme will be the one at which it works best. This pH also determines the reaction rate. The enzyme reaction speed will decline if the pH is higher or lower than the optimum pH. Because the enzyme’s active sites are altered, pH can affect the activity. A pH lower than the ideal pH can cause the enzyme’s active sites to become negatively charged, repel substrate molecules and reduce reaction speed. The opposite can happen at pH above optimum. At this point, the enzyme’s active site could become less positively charged, repelling the substrate molecules and reducing reaction speed. Christian Anfinsen (Nobel Prize winner in Chemistry), discovered this phenomenon when he studied enzymes back in 1957. The effects of pH have been extensively studied since then (Chin and al., 2016,). Fandino and Garcia’s (2020) research showed, for instance, that altering pH in the environment can change the activity of enzymes by changing their structure and catalytic activities.