Isolation and crystallization of gastricsin from human gastric juice.

The samples of human gastric juice were collected from patients of the University Hospital and the Veterans’ Administration Hospital in Oklahoma City, Oklahoma. The secretion of gastric juice was stimulated by injecting intravenously 10 units of insulin immediately before starting each collection. The gastric juice was collected in jars, cooled to 4”, and kept at this temperature. Samples from several patients were pooled, dialyzed against distilled water, and lyophilized in batches of about 250 ml. Hog pepsin, crystallized twice, was purchased from General Biochemicals, Chagrin Falls, Ohio. The crystalline rennin was from Nutritional Biochemicals Corporation, Cleveland, and the bovine hemoglobin substrate from Pentex, Kankakee, Illinois.