2.29 understand the role of digestive enzymes, including the digestion of starch to glucose by amylase and maltase, the digestion of proteins to amino acids by proteases and the digestion of lipids to fatty acids and glycerol by lipases

Enzyme	Site of production	Site of action	pH	Substrate	Products
Salivary amylase	Salivary glands	Mouth	weak acid to neutral	Starch	Glucose
Pancreatic amylase	Pancreas	Small intestine	neutral to alkaline	Starch	Glucose
Pepsin (type of protease)	Stomach	Stomach	strong acid	Protein	Amino acids
Trypsin (type of protease)	Pancreas	Small intestine	neutral to alkaline	Protein	Amino acids
Intestinal protease	Small intestine	Small intestine	alkaline	Protein	Amino acids
Lipase	Pancreas	Small intestine	alkaline	Lipids	Fatty acids and glycerol

Enzymes that work in the small intestine all have a neutral-alkaline pH. This is because bile is released into the small intestine to neutralise the stomach acid carried into the small intestine. Bile is alkaline, stomach acid is acidic, therefore they can be neutralised.
Because bile is alkaline and is released to small intestine, enzymes in the small intestine will have an optimum pH of alkaline.

Enzymes that work in the stomach have an acidic pH. This is because of the hydrochloric acid in the stomach.