The Estimation of Pepsin With Hemoglobin

Abstract

A number of methods have been described for the estimation of peptic activity, many of which are accurate and convenient for comparative experiments but none of which give results which are accurately reproducible with different preparations of the protein used. This variation is due to the difficulty involved in obtaining reproducible protein preparations and keeping them unchanged. Hemoglobin has been chosen as the protein substrata for the estimation of pepsin because it is easily prepared in large quantities, because it can be stored in solution for a long time without change, because it is rapidly digested, and because the rate at which it is digested by a given pepsin solution does not vary from one hemoglobin preparation to another. Not only is hemoglobin a reproducible protein which can be brought to reproducible conditions but the conditions of digestion have been so chosen that reasonable variations in these conditions have little effect on the amount of digestion. In general the procedure used to estimate pepsin is this. A pepsin solution is added to acidified hemoglobin. After 5 minutes trichloracetic acid is added. The resulting precipitate which contains all the pigment and all the undigested hemoglobin is faltered off. The filtrate contains an amount of digested hemoglobin which is a measure of the amount of pepsin used. This digested hemoglobin is estimated by the blue color it gives with the phenol reagent, which reacts with tyrosine, tryptophane and cysteine groups, tyrosine being used as a standard. The intensity of this color is proportional to the amount of enzyme used and to the time of digestion.

Serum group I pepsinogen levels in patients with peptic ulcer and normal subjects.

“…PAO was calculated by adding the two highest consecutive 15 min outputs and multiplying by two. Gastric pepsin concentration was determined by the minor modification of the method of Anson and Mirsky (1932), and was expressed by L-tyrosine per ml of gastric juice produced by hemoglobin digestion with the use of bovine hemoglobin as a substrate. Pepsin output was expressed by the following three factors; basal pepsin output (BPO), stimulated pepsin output (SPO) and peak pepsin output (PPO).…”

Chicken and Rabbit Antibodies against Porcine Pepsinogen A

“…The purified porcine zymogen was characterized by native electrophoresis (Samloff, 1969), SDS electrophoresis, peptic activity estimation (Anson and Mirsky, 1932), ELISA and Western blotting and further used as an immunogen to develop rabbit and chicken specific antibodies. According to SDS electrophoresis results isolated porcine pepsinogen A was contaminated by porcine serum albumin slightly.…”

Comparative Study on Gastric Secretory Function between Benign Gastric Polyp and Elevated Type of Early Stomach Cancer with Special Reference to Histological Findings of Gastric Mucosa

“…Each fraction was examined for volume, titratable acidity using a pH-stat and peptic activity according to a slightly modified method of Anson-Mirsky (1933). Proteolytic activity of gastric juice at pH 1.5 was expressed in mg of tyrosine produced from bovine hemoglobin in 1 min during the digestion experiment by 1 ml of native gastric juice.…”