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… (More)
The viscosity of a protein solution is increased by the denaturation of the protein. This is true both when there is the formation of protein aggregates which occlude water and when there is no aggregation. Under certain conditions, as a result of the aggregation following denaturation, a solution containing only one per cent of protein may be converted… (More)
1. The processes of denaturation and coagulation of hemoglobin are like those of other proteins. 2. When hemoglobin is denatured it is probably depolymerized into hemochromogen. 3. When other proteins are denatured they, too, are probably depolymerized. Conversely, native proteins can be regarded as aggregates of denatured proteins. 4. The globins and… (More)
The denaturation of hemoglobin by salicylate in neutral solution is completely reversible. There is a mobile equilibrium between native and denatured hemoglobin in neutral salicylate solution. The higher the salicylate concentration the greater is the percentage denaturation. When there is a mobile equilibrium between the native and denatured forms of a… (More)
The Reversibility of Coagulation It has already been shown that the coagulation of hemoglobin appears to be reversible. One can prepare from completely coagulated hemoglobin soluble, crystalline hemoglobin which by the tests so far tried is indistinguishable from ordinary native hemoglobin (Mirsky and Mason (13)). Since hemoglobin is a typical coagulable… (More)
The formation from hemoglobin of split products not precipitable by trichloracetic acid is taken as a measure of tryptic activity. The split products are estimated colorimetrically. Many measurements of tryptic activity can be made in a short time and different samples of hemoglobin yield the same results.
1. A method is described for estimating the heme in yeast and bees' muscles as pyridine hemochromogen. 2. The difficulties of the method are discussed. 3. The heme as given by the pyridine method is responsible for about 40 per cent of the total iron.
Cyanide can react with globin hemochromogen in two different ways. In the first reaction cyanide combines with globin hemochromogen without displacing or competing with globin. In the second reaction cyanide displaces globin.
1. Cyanide hemochromogen probably contains one cyanide group per heme group. 2. The equilibrium between pyridine hemochromogen and its components, pyridine and reduced heme, is complicated to an unknown extent by the precipitation of reduced heme and the aggregation of pyridine hemochromogen. 3. These complications were not taken into account in R. Hill's… (More)
As a preliminary to the study of the reversal of the coagulation of hemoglobin several methods are described for the preparation of completely denatured and coagulated hemoglobin and the evidence is given that hemoglobin is a typical coagulable protein.