Gastric juice contains two active digestive enzymes, pepsin and gastric lipase, as stated by InnerBody. These two enzymes are produced by the chief cells lining gastric pits in the stomach.
The stomach is an organ in the body that breaks down masticated food from the mouth using acids, digestive enzymes and a mechanical churning motion. The resulting thick liquid mixture, called "chyme," is passed into the small intestines to continue the digestion process.
Pepsin is a digestive enzyme used to break down protein while gastric lipase is used to break fats down into fatty acids and diglycerides. The former is produced in its active form by the chief cells, but not the latter. The stomach actually produces pepsinogen, the inactive form of pepsin. Pepsinogen becomes active on contact with hydrochloric acid in the stomach.