Dietetics for Nurses

by Fairfax T. Proudfit

TABLE OF ENZYMES[54]

Source and Action of Enzymes

			Enzymes	Where chiefly found	Action
Act upon carbohydrates			Ptyalin (salivary amylase)	Salivary secretions	Converts starch to maltose
			Amylopsin (pancreatic amylase)	Pancreatic juice	Converts starch to maltose
			Liver diastase	Liver	Converts glycogen to glucose
			Muscle diastase	Muscles	Converts glycogen to glucose
			Invertase (sucrase)	Intestinal juice	Converts glycogen to glucose and fructose
			Maltase	Intestinal juice	Converts maltose to glucose
			Lactase	Intestinal juice	Converts lactose to glucose and galactose
			Glycolytic enzymes	Muscles, etc.	Split and oxidize glucose
Acts on fats			Lipase (steapsin)	Gastric, and pancreatic secretions, blood and tissues	Splits fats to fatty acids and glycerin
Act on proteins			Pepsin	Gastric juice	Splits proteins to proteoses and peptones
			Trypsin	Pancreatic juice	Splits proteins to proteoses, peptones, polypeptids and amino acids
			Erepsin	Intestinal juice	Splits peptones to amino acids and ammonia
			Autolytic enzymes	Tissue generally	Split body proteins to simpler substances
Act on purins			Guanase	Thymus, adrenals, pancreas	Changes guanin to xanthin
			Adenase	Spleen, pancreas, liver	Changes adenin to hypoxanthin
			Oxidases	Lungs, liver, muscles, etc.	Changes hypoxanthin to xanthin and to uric acid

Classification of Enzymes.—Sherman classifies the enzymes of the body according to their effects:

1. The hydrolytic enzymes:

(a) Proteolytic or protein-splitting enzymes.
(b) Lipolytic or fat-splitting enzymes.
(c) Amylolytic or starch-splitting enzymes.
(d) Sugar-splitting enzymes.

2. The coagulating enzymes, such as thrombin or thrombase (the fibrin ferment) and rennin, which causes the clotting of milk.

3. The oxidizing enzymes or oxidases (which, if the oxidation be accompanied by a splitting off of amino groups, may be called “deaminizing” enzymes).

4. The reducing enzymes or “reductases.”