J.Jpn. Surg. Soc.. 55(8): 899-907, 1954

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Original article

A CHEMICAL STUDY OF THE PROTEINS CONTAINED IN THE WALL OF THE DIGESTIVE TRACT

On the assumption that the local difference in the incidence of so-called peptic ulcer might be attributed to the existence of some different local dispositions in the wall of the digestive tract, the author examined for comparison the nature of the protein constituting each mucosa and muscle of the digestive tract both electrophoretically and enzymologically, with the following results:
The protein components were extracted with buffer solution of pH 9.3 (boric acid + potassium chloride + sodium carbonate) from the mucous membranes of the jejunum and of the fundic and pyloric areas of the stomach, and with 0.5M solution of potassium chloride, from the muscles of the fundic and pyloric areas of the stomach.
1) As disclosed on the electropherograms obtained by Tiselius' Schlieren-diagonal method and on the paperelectropherograms, the mucous membranes of the jejunum, the fundic and the pyloric area were markedly varied in the nature of the proteins they contained.
2) The mucosa proteins of the fundic and pyloric areas were found to contain pepsinogen, of which the volumetric relation was 16 : 1 as measured with the peptic activity of activaed pepsin as the standard. The mucosa protein of the jejunum contained no pepsinogen.
3) That fraction of the extracted mucosa protein in which a mobility of 11.3×10-5 cm²/volt/sec. was presented in phosphate buffer solution of pH 8.03 and 0.1 ionic strength was pepsinogen, showing peptic activity in a solution acidified by hydrochloric acid.
4) The presence or absence in those mucosa proteins of any local difference in the power of resistance to peptic activity was undeterminable.
5) The power of resistance to tryptic activity was varied for the following different mucosa proteins in the order of strength denoted ;
jejunal mucosa protein>pyloric mucosa protein＞fundic mucosa protein
6) The muscle proteins of the stomach were not varied at all in the fundic region and in the pyloric region as to their electrophoretic nature and their resistance to peptic and tryptic activity They must therefore be proteins of the same chemical nature.
The Tomoda Surgical Clinic has demonstrated the existence of local difference in the digestive tract by measuring potential difference on the mucous membrane of the digestive tract and by determining isoelectric point in its surface epithelium.
The author's comparative study of the chemical natures of the mucosa proteins of the digestive tract has also disclosed the presence of such local difference in that tract.
(author's abstract)

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