In two previous communications the authors have described a synthesis of protein by pepsin in a concentrated peptic hydrolysate of albumin (1) ; and the effect of temperature on this synthesir (2). The justification for describing the synthetic product as protein is discussed in our previous paper (2). In these communications the optimum hydrogen ion concentration was stated to be pH 4.0; but t...

The hydrogen ion concentration (1) of many solutions and of culture media is readily determined by means of buffer solutions and suitable indicators. The usual procedure, in determining calorimetrically the hydrogen ion concentration, requires a considerable volume of solution. Frequently the quantity of solution available in experiments upon plants or animals is extremely limited in amount. It...

In previous studies we have demonstrated a hydrogen ion concentration gradient across the mucus on rat and rabbit fundic mucosa, in vivo and in vitro respectively, observations which support the possibility of a 'mucus-bicarbonate' protective barrier. In the present studies we have demonstrated a similar gradient across the mucus on human gastric mucosa in vitro. The minimum mean hydrogen ion c...