the effects that enzymes can have on substrates

The optimum pH in the duodenum is produced by the secretion of sodium hydrogencarbonate. The optimum pH in the stomach is produced by the secretion of hydrochloric acid. Different parts of the digestive system produce different enzymes. Cellular enzymes will work best within this pH range. The changes are usually, though not always, permanent.Įnzymes work inside and outside cells, for instance in the digestive system where cell pH is kept at 7.0pH to 7.4pH. Again, the shape of the enzyme, along with its active site, will change.Įxtremes of pH also denature enzymes. Amino acids that attracted each other may no longer be. This contributes to the folding of the enzyme molecule, its shape, and the shape of the active site.Ĭhanging the pH will affect the charges on the amino acid molecules. Within the enzyme molecule, positively and negatively charged amino acids will attract. Many amino acids in an enzyme molecule carry a charge. Changing the pH of its surroundings will also change the shape of the active site of an enzyme. The rate of reaction will be affected, or the reaction will stop.Ī graph to show the effect of temperature on enzyme activity: The effect of pHĮnzymes are also sensitive to pH. The enzyme, including its active site, will change shape and the substrate no longer fit. High temperatures will break these forces. This structure is held together by weak forces between the amino acid molecules in the chain. This chain is not straight – it twists and folds as different amino acids in the chain are attracted to, or repel each other.Įach enzyme is comprised of proteins made of these twisting and folding amino acids, and therefore the enzyme has a unique shape. Proteins are chains of amino acids joined end to end. Įnzymes therefore work best at a particular temperature. Higher temperatures disrupt the shape of the active site, which will reduce its activity, or prevent it from working. This not true of the enzymes in all organisms. The human body is maintained at 37☌ as this is the temperature at which the enzymes in our body work best. TemperatureĪt low temperatures, the number of successful collisions between the enzyme and substrate is reduced because their molecular movement decreases.

The effects that enzymes can have on substrates