The enzyme amylase in the pancreas causes the decomposition of starch. During the chemical reaction, starch breaks down into disaccharides, lactase, sucrase and maltase in the form of pure sugar. Disaccharides are broken down into monosaccharides. Lactase transformed into lactose, then into glucose and galactose, sucrase transformed sucrose into glucose and fructose, these are all forms of sugars. These sugars may not all be used by the body. Maltase breaks down the glucose molecules of form 2 of maltose. Protein-Stomach Pepcid and HCI break down proteins. These proteins continue during the chemical reaction to transform into polypeptides. In the small intestine trypsin breaks down proteins and polypeptides into dipeptides. Then dipeptides are transformed into chymotrypsin, decomposition of proteins and polypeptides into dipeptides. Carboxypeptidase breaks down polypeptides and dipeptides into amino acids. Aminopeptidase breaks down polypeptides and dipeptides into amino acids. Dipeptidase cleaves dipeptides into amino acids. Amino acids are mostly used by the digestive process; They are the building blocks of proteins. Fats begin the chemical digestive process in the mouth, perhaps because many fats take longer to break down. Lingual lipase plays a minor role in initiating fat digestion. The stomach has a huge amount of chemical reactions going on at once.