Digestive enzymes

The groups of enzymes involved in the breakdown of food are:

Carbohydrases break down carbohydrates:

\mathbf{carbohydrate}\; \overset{\mathbf{carbohydrase}}{\rightarrow}\; \mathbf{simple\; sugars}

Starch is a type of carbohydrate. The carbohydrase that breaks down starch is amylase:

\mathbf{starch}\; \overset{\mathbf{amylase}}{\rightarrow}\; \mathbf{glucose}

Proteases break down proteins:

\mathbf{protein}\; \overset{\mathbf{protease}}{\rightarrow}\; \mathbf{amino\; acids}

Lipases break down lipids:

\mathbf{lipid}\; \overset{\mathbf{lipase}}{\rightarrow}\; \mathbf{fatty\; acids}\;\mathbf{+\; glycerol}

Carbohydrases

Carbohydrases break down carbohydrates in several regions of the digestive system.

Most of the carbohydrate we eat is starch, so this will be the main substrate in the early part of digestion for enzyme action.

Region of digestive systemEnzymeWhere producedSubstrateBroken down into
MouthSalivary amylaseSalivary glandsStarchMaltose
Small intestine - DuodenumPancreatic amylasePancreasStarchMaltose
Small intestine - IleumAmylaseWall of ileumMaltoseGlucose

Proteases

Proteases break down proteins in several regions of the digestive system.

Region of digestive systemEnzymeWhere producedSubstrateBroken down into
StomachProtease - pepsinGastric glands in stomachProteinsBegins the breakdown into amino acids
Small intestine - DuodenumProtease - trypsinPancreasProteinsContinues the breakdown into amino acids
Small intestine - IleumProtease - peptidaseWall of ileumPeptidesCompletes the breakdown into amino acids

Lipases

Lipases break down lipids in one region of the digestive system.

Region of digestive systemEnzymeWhere producedSubstrateBroken down into
Small intestine - DuodenumLipasePancreasLipidsFatty acids and glycerol