Why enzyme denatured

Enzymes are also sensitive to pH. Changing the pH of its surroundings will also change the shape of the active site of an enzyme. Many amino acids in an enzyme molecule carry a charge. Within the enzyme molecule, positively and negatively charged amino acids will attract. This contributes to the folding of the enzyme molecule, its shape, and the shape of the active site.

Changing the pH will affect the charges on the amino acid molecules. Amino acids that attracted each other may no longer be.

Again, the shape of the enzyme, along with its active site, will change. Extremes of pH also denature enzymes. The changes are usually, though not always, permanent. Enzymes work inside and outside cells, for instance in the digestive system where cell pH is kept at 7.

Cellular enzymes will work best within this pH range. Different parts of the digestive system produce different enzymes. These have different optimum pHs. The optimum pH in the stomach is produced by the secretion of hydrochloric acid. The optimum pH in the duodenum is produced by the secretion of sodium hydrogencarbonate.

The following table gives examples of how some of the enzymes in the digestive system have different optimum pHs:. A graph to show the effect of pH on an enzyme's activity:. Enzymes are generally globular proteins, acting alone or in larger complexes. Like all proteins, enzymes are linear chains of amino acids that fold to produce a three-dimensional structure.

The sequence of the amino acids specifies the structure which in turn determines the catalytic activity of the enzyme. Although structure determines function, a novel enzyme's activity cannot yet be predicted from its structure alone. Enzyme structures unfold denature when heated or exposed to chemical denaturants and this disruption to the structure typically causes a loss of activity. So, they are molecules that speed up a chemical reaction without being changed by the reaction.

Enzymes are folded into complex 3D shapes that allow smaller molecules to fit into them. The place where these molecules fit is called the active site. In the lock and key hypothesis , the shape of the active site matches the shape of its substrate molecules.

This makes enzymes highly specific. Each type of enzyme can usually catalyse only one type of reaction some may catalyse a few types of reactions.