How does pH affect an enzyme?

Answer 1

When the pH level rises, the enzyme's bonds become weakened, changing the enzyme's structure and disabling its function (so its substrates can't enter its active site).

Enzymes, like all proteins, are folded into three-dimensional shapes (called tertiary structure). Their structures are determined by their amino acid sequences and the conditions of the solution they're in. The acidity of a solution can affect the tertiary structure of the protein, making it more or less accessible to the substrates or ligands(molecules that affect enzyme activity but are not processed by the enzyme).

In most cells, enzymes acting in the cytosol and mitochondria have pH optima of around 7.2 (physiological pH). However, some enzymes in these compartments actually work better at lower pH, which occurs when the cells are stressed. The vacuole and apoplastic space (between plasma membrane and cell wall) of plant cells is much more acidic, therefore enzymes acting there have pH optima between 3-5. In the human digestive tract, there are enzymes operating at basic pH (mouth and intestine) and highly acidic pH (stomach).

So the effect of pH depends on the "native" conditions that the enzyme is optimized to use.

Answer 2

pH is the degree of acidity or alkalinity. Each enzyme is different. They tend to work at the optimum pH level of the environment in which they are found. Enzymes do not have pH, but are influenced by pH, which is a property of the solution in which the enzymes work. A change in pH will affect the shape and/or the electrical charge of an enzyme and/or the substrate. This will alter the enzyme's ability to perform its activity, which basically means it won't be able to allow the substrate to bind to its active site and undergo catalysis.

Answer 3

As you may know, the pH level is how acidic or alkaline an environment is. Certain enzymes, for example salivary amylase in the mouth, work best at a certain pH level. If the pH level is too high or low, then the enzymes will either slow down and be rendered useless, or decompose.

Answer 4

If the pH is higher it is more basic so it can hinder the enyzmes reaction rate, however if the pH is lower, its more acidic and will increase the reaction rate of the enzymes.