Amylopsin (also known as pancreatic amylase) does not act on proteins. It acts on starch carbohydrates. Pepsin, trypsin, and erepsin (also known as peptidase) act on proteins. Erepsin also acts on peptides.

Amylopsin (also known as pancreatic amylase) is an enzyme present in the duodenum (a part of the small intestine). Amylopsin acts on starch carbohydrates and converts them into maltose.

Enzymes are proteins by nature. They are chemical substances produced in a living body that help to speed up the rate of chemical reactions in the body. Hence, they are also called 'biocatalysts'.

Pepsin is an enzyme contained in gastric juice. Pepsin acts on proteins and converts them into proteoses and peptones.

Invertase (also known as sucrase) is an enzyme present in the ileum (a part of the small intestine). Invertase acts on sucrose and converts it into glucose and fructose.

Erepsin (also known as peptidase) is an enzyme contained in intestinal juice. Erepsin acts on proteins and peptides. It converts them into amino acids.

Trypsin is an enzyme contained in pancreatic juice. Trypsin acts on proteins and converts them into proteoses, peptones, peptides, and amino acids.

Pancreatic juice (secreted by the pancreas) contains three enzymes, namely amylopsin or pancreatic amylase (acts on starch), trypsin (acts on proteins), and steapsin or lipase (acts on emulsified fats).

The salivary glands in the mouth secrete saliva, which contains an enzyme called ptyalin (salivary amylase). Ptyalin acts on starch and converts it into maltose.

Ptylain does not act on fats. It acts on starch carbohydrates. Steapsin and lipase act on fats.

The gastric glands secrete gastric juice which contains three enzymes, namely pepsin (acts on proteins), rennin (acts on milk proteins or caseinogen), and gastric lipase (acts on fats). Of these, rennin is produced only in children.

Steapsin does not act on carbohydrates. It acts on fats. Ptyalin, amylopsin (also known as pancreatic amylase), and invertase (also called sucrase) act on starch carbohydrates.

The large intestine does not secrete any enzymes. Undigested food and water pass through the large intestine. It absorbs water, but the undigested food passes into the rectum and is expelled from the anus.

The liver secretes a chemical compound called bile, which contains no enzymes. Bile is a brownish-green fluid which is stored in the gall bladder. Bile emulsifies fats and makes the food alkaline.

Enzymes help to quicken the rate of chemical reactions in a living body and do not undergo any changes themselves during this process.