scholarly journals THE COLLOIDAL BEHAVIOR OF SERUM GLOBULIN

1922 ◽  
Vol 5 (1) ◽  
pp. 35-44 ◽  
Author(s):  
David I. Hitchcock
Keyword(s):  
Potential Difference ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Serum Globulin ◽  
Hydrogen Ion Concentration ◽  
Egg Albumin ◽  
Electrometric Titration ◽  
Acids And Bases ◽  
Protein Serum ◽  
Colloidal Behavior

1. The globulin prepared from ox serum by dilution and precipitation with carbon dioxide has been found, by electrometric titration experiments, to behave like an amphoteric electrolyte, reacting stoichiometrically with acids and bases. 2. The potential difference developed between a solution of globulin chloride, phosphate, or acetate and a solution of the corresponding acid, free from protein, separated from the globulin by a collodion membrane, was found to be influenced by hydrogen ion concentration and salt concentration in the way predicted by Donnan's theory of membrane equilibrium. In experiments with sodium globulinate and sodium hydroxide it was found that the potential difference could be similarly explained. 3. The osmotic pressure of such solutions could be qualitatively accounted for by the Donnan theory, but exhibited a discrepancy which is explicable by analogy with certain experiments of Loeb on gelatin. 4. The application of Loeb's theory of colloidal behavior, which had previously been found to hold in the case of gelatin, casein, egg albumin, and edestin, has thus been extended to another protein, serum globulin.

scholarly journals THE COLLOIDAL BEHAVIOR OF EDESTIN

1922 ◽  
Vol 4 (5) ◽  
pp. 597-615 ◽  
Author(s):  
David I. Hitchcock
Keyword(s):  
Salt Concentration ◽  
Potential Difference ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Acid Salt ◽  
Salt Solutions ◽  
Hydrogen Ion Concentration ◽  
Egg Albumin ◽  
Acids And Bases ◽  
Colloidal Behavior

1. It has been shown by titration experiments that the globulin edestin behaves like an amphoteric electrolyte, reacting stoichiometrically with acids and bases. 2. The potential difference developed between a solution of edestin chloride or acetate separated by a collodion membrane from an acid solution free from protein was found to be influenced by salt concentration and hydrogen ion concentration in the way predicted by Donnan's theory of membrane equilibrium. 3. The osmotic pressure of such edestin-acid salt solutions was found to be influenced by salt concentration and by hydrogen ion concentration in the same way as is the potential difference. 4. The colloidal behavior of edestin is thus completely analogous to that observed by Loeb with gelatin, casein, and egg albumin, and may be explained by Loeb's theory of colloidal behavior, which is based on the idea that proteins react stoichiometrically as amphoteric electrolytes and on Donnan's theory of membrane equilibrium.

scholarly journals CHANGES IN THE APPARENT CYTOPLASMIC HYDROGEN ION CONCENTRATION OF AMEBA DUBIA ON INJECTION OF EGG ALBUMIN

1944 ◽  
Vol 28 (2) ◽  
pp. 95-102 ◽  
Author(s):  
A. Marshak
Keyword(s):  
Hydrogen Ion ◽  
Ion Concentration ◽  
Phenol Red ◽  
Alkaline Ph ◽  
Cent Solution ◽  
O2 Uptake ◽  
Marked Rise ◽  
Hydrogen Ion Concentration ◽  
Egg Albumin ◽  
The One

1. Egg albumin when injected into an ameba or discharged into the solution about it raises the apparent pH of the cytoplasm of the ameba. 2. With time the cytoplasm returns to the original pH 6.9 if the nucleus is present. Amebae that have received repeated injections of albumin in some cases extrude their nuclei. In these cells the cytoplasm remains at the more alkaline pH induced by the albumin for at least 12 hours. 3. When a 2 per cent solution of albumin is introduced into a suspension of amebae there is a temporary marked rise in the rate at which CO2 is given off with no corresponding rise in O2 uptake. 4. The results observed can be explained if the albumin discharged onto the surface of the ameba rapidly enters the cell and there becomes distributed in a phase of the cytoplasm other than the one which contains the phenol red.

scholarly journals THE EFFECT OF VARIOUS ACIDS ON THE DIGESTION OF PROTEINS BY PEPSIN

1919 ◽  
Vol 1 (6) ◽  
pp. 607-612 ◽  
Author(s):  
J. H. Northrop
Keyword(s):  
Acetic Acid ◽  
The State ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
Pepsin Digestion ◽  
Marked Influence ◽  
Egg Albumin ◽  
Blood Albumin ◽  
Salt Action

1. At equal hydrogen ion concentration the rate of pepsin digestion of gelatin, egg albumin, blood albumin, casein, and edestin is the same in solutions of hydrochloric, nitric, sulfuric, oxalic, citric, and phosphoric acids. Acetic acid diminishes the rate of digestion of all the proteins except gelatin. 2. There is no evidence of antagonistic salt action in the effect of acids on the pepsin digestion of proteins. 3. The state of aggregation of the protein, i.e. whether in solution or not, and the viscosity of the solution have no marked influence on the rate of digestion of the protein.

scholarly journals THE COMBINATION OF ENZYME AND SUBSTRATE

1919 ◽  
Vol 2 (2) ◽  
pp. 113-122 ◽  
Author(s):  
John H. Northrop
Keyword(s):  
Quantitative Method ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Albumin Solution ◽  
Hydrogen Ion Concentration ◽  
Egg Albumin ◽  
Insoluble Substrate

1. A quantitative method for the determination of pepsin is described depending on the change in conductivity of a digesting egg albumin solution. 2. The combination of pepsin with an insoluble substrate has been followed by this method. 3. The amount of pepsin removed from solution by a given weight of substrate is independent of the size of the particles of the substrate. 4. There is an optimum zone of hydrogen ion concentration for the combination of enzyme and substrate corresponding to the optimum for digestion. 5. It is suggested that the pepsin combines largely or entirely with the ionized protein.

scholarly journals STUDIES IN THE PHYSICAL CHEMISTRY OF THE PROTEINS

1922 ◽  
Vol 4 (6) ◽  
pp. 697-722 ◽  
Author(s):  
Edwin Joseph Cohn
Keyword(s):  
Protein Molecule ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Physicochemical Constant ◽  
Serum Globulin ◽  
Hydrogen Ion Concentration ◽  
Heterogeneous Equilibrium ◽  
Protein Ions ◽  
Pure Protein ◽  
Milk Casein

1. Two proteins of the globulin type, serum globulin and tuberin, and the protein of milk, casein, have been purified (a) of the other proteins and (b) of the inorganic electrolytes with which they exist in nature. The methods that were employed are described. 2. All three proteins were found to be only very slightly soluble in water in the pure uncombined state. The solubility of each was accurately measured at 25.0° ± 0.1°C. The most probable solubility of the pseudoglobulin of serum was found to be 0.07 gm. in 1 liter; of tuberin 0.1 gm. and of casein 0.11 gm. The methods that were employed in their determination are described. 3. Each protein investigated dissolved in water to a constant and characteristic extent when the amount of protein precipitate with which the solution was in heterogeneous equilibrium was varied within wide limits. The solubility of a pure protein is therefore proposed as a fundamental physicochemical constant, which may be used in identifying and in classifying proteins. 4. The concentration of protein dissolved must be the sum of the concentration of the undissociated protein molecule which is in heterogeneous equilibrium with the protein precipitate, and of the concentration of the dissociated protein ions. 5. The dissociated ions of the dissolved protein give a hydrogen ion concentration to water that is also a characteristic of each protein.

scholarly journals STUDIES ON THE REGULATION OF OSMOTIC PRESSURE

1922 ◽  
Vol 4 (5) ◽  
pp. 585-589 ◽  
Author(s):  
Walter W. Palmer ◽  
Dana W. Atchley ◽  
Robert F. Loeb
Keyword(s):  
Osmotic Pressure ◽  
Isoelectric Point ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Nacl Solution ◽  
Hydrogen Ion Concentration ◽  
Egg Albumin

Egg albumin, like gelatin, influences the conductivity of a 0.6 per cent NaCl solution in two ways: (a) At an hydrogen ion concentration of about pH 3.0, increasing concentrations increase the conductivity. (b) Near the isoelectric point of albumin and at the pH of the blood, increasing concentrations of albumin decrease the conductivity of the NaCl solution.

scholarly journals STUDIES ON THE REGULATION OF OSMOTIC PRESSURE

1921 ◽  
Vol 3 (6) ◽  
pp. 801-806 ◽  
Author(s):  
Walter W. Palmer ◽  
Dana W. Atchley ◽  
Robert F. Loeb
Keyword(s):  
Sodium Chloride ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
Specific Conductivity ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Degree Of Ionization ◽  
Hydrogen Ion Concentration ◽  
Egg Albumin ◽  
Cent Sodium

1. In pure gelatin solutions the conductivity of the solution increases with increasing concentrations, regardless of the hydrogen ion concentration. The actual value of the specific conductivity is greater at that reaction where the degree of ionization is greater. 2. The addition of gelatin in increasing concentrations to a 0.6 per cent sodium chloride solution affects the conductivity of that solution in two ways: (a) At pH 3.3, (where gelatin is highly ionized) the conductivity increases with each added increment of gelatin. (b) At pH 5.1 and 7.4 (where gelatin is less highly ionized) the conductivity decreases with each added increment of gelatin. A similar study is being made of crystalline egg albumin.

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