Addition Of Neutral Salts Research Articles

Neutral Salt Addition Compounds of Alkaline Earth Glutamates and Aspartates

Research Article| January 01 1927 Neutral Salt Addition Compounds of Alkaline Earth Glutamates and Aspartates Winston Kennay Anslow; Winston Kennay Anslow 1The Department of Biochemistry and Pharmacology, National Institute for Medical Research, Hampstead, N.W. 3 Search for other works by this author on: This Site PubMed Google Scholar Harold King Harold King 1The Department of Biochemistry and Pharmacology, National Institute for Medical Research, Hampstead, N.W. 3 Search for other works by this author on: This Site PubMed Google Scholar Biochem J (1927) 21 (5): 1168–1178. https://doi.org/10.1042/bj0211168 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Cite Icon Cite Get Permissions Citation Winston Kennay Anslow, Harold King; Neutral Salt Addition Compounds of Alkaline Earth Glutamates and Aspartates. Biochem J 1 January 1927; 21 (5): 1168–1178. doi: https://doi.org/10.1042/bj0211168 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsBiochemical Journal Search Advanced Search This content is only available as a PDF. © 1927 CAMBRIDGE UNIVERSITY PRESS1927 Article PDF first page preview Close Modal You do not currently have access to this content.

STUDIES ON THE BACTERIOPHAGE OF D'HERELLE

Addition of neutral salts to the lytic filtrate results in an increased rate of inactivation of the latter when alcohol is added to it. This effect of salts is the more marked the higher the valency of the cation. Conversely, removal by dialysis of salts originally present in the lytic filtrate tends to render lytic agent less sensitive to alcohol. Restitution of the original salt content to the dialyzed filtrate tends to bring the sensitiveness to alcohol in the dialyzed filtrate to the level of the non-dialyzed control. It appears, therefore, that inactivation of the lytic agent by alcohol depends directly on the rate of precipitation of the coagulable constituents of the medium, and is not the result of a direct toxic action of alcohol on "bacteriophagum intestinale." Considered in association with our earlier findings, these results speak in favor of the chemical nature of the agent of transmissible lysis.

THE ORIGIN OF THE ELECTRICAL CHARGES OF COLLOIDAL PARTICLES AND OF LIVING TISSUES

1. When a solution of a salt of gelatin or crystalline egg albumin is separated by a collodion membrane from a watery solution (free from protein) a potential difference is set up across the membrane in which the protein is positively charged in the case of protein-acid salts and in which the protein is negatively charged in the case of metal proteinates. The turning point is the isoelectric point of the protein. 2. Measurements of the pH of the (inside) protein solution and of the outside watery solution show that when equilibrium is established the value pH inside minus pH outside is positive in the case of protein-acid salts and negative in the case of metal proteinates. This is to be expected when the P.D. is caused by the establishment of a Donnan equilibrium, since in that case the pH should be lower outside than inside in the case of a protein-acid salt and should be higher outside than inside in the case of a metal proteinate. 3. At the isoelectric point where the electrical charge is zero the value of pH inside minus pH outside becomes also zero. 4. It is shown that a P.D. is established between suspended particles of powdered gelatin and the surrounding watery solution and that the sign of charge of the particles is positive when they contain gelatin-acid salts, while it is negative when the powdered particles contain metal gelatinate. At the isoelectric point the charge is zero. 5. Measurements of the pH inside the powdered particles and of the pH in the outside watery solution show that when equilibrium is established the value pH inside minus pH outside is positive when the powdered particles contain a gelatin-acid salt, while the value pH inside minus pH outside is negative when the powdered particles contain Na gelatinate. At the isoelectric point the value pH inside minus pH outside is zero. 6. The addition of neutral salts depresses the electrical charge of the powdered particles of protein-acid salts. It is shown that the addition of salts to a suspension of powdered particles of gelatin chloride also diminishes the value of pH inside minus pH outside. 7. The agreement between the values 58 (pH inside minus pH outside) and the P. D. observed by the Compton electrometer is not only qualitative but quantitative. This proves that the difference in the concentration of acid (or alkali, as the case may be) in the two phases is the only cause for the observed P.D. 8. The Donnan theory demands that the P.D. of a gelatin chloride solution should be 1(1/2) times as great as the P.D. of a gelatin sulfate solution of the same pH and the same concentration (1 per cent) of originally isoelectric gelatin. This is found to be correct and it is also shown that the values of pH inside minus pH outside for the two solutions possess the ratio of 3:2. 9. All these measurements prove that the electrical charges of suspended particles of protein are determined exclusively by the Donnan equilibrium.

THE RÔLE OF THE ACTIVITY COEFFICIENT OF THE HYDROGEN ION IN THE HYDROLYSIS OF GELATIN

1. The hydrolysis of gelatin at a constant hydrogen ion concentration follows the course of a monomolecular reaction for about one-third of the reaction. 2. If the hydrogen ion concentration is not kept constant the amount of hydrolysis in certain ranges of acidity is proportional to the square root of the time (Schütz's rule). 3. The velocity of hydrolysis in strongly acid solution (pH less than 2.0) is directly proportional to the hydrogen ion concentration as determined by the hydrogen electrode i.e., the "activity;" it is not proportional to the hydrogen ion concentration as determined by the conductivity ratio. 4. The addition of neutral salts increases the velocity of hydrolysis and the hydrogen ion concentration (as determined by the hydrogen electrode) to approximately the same extent. 5. The velocity in strongly alkaline solutions (pH greater than 10) is directly proportional to the hydroxyl ion concentration. 6. Between pH 2.0 and pH 10.0 the rate of hydrolysis is approximately constant and very much greater than would be calculated from the hydrogen and hydroxyl ion concentration. This may be roughly accounted for by the assumption that the uncombined gelatin hydrolyzes much more rapidly than the gelatin salt.

DONNAN EQUILIBRIUM AND THE PHYSICAL PROPERTIES OF PROTEINS

1. It is shown that a neutral salt depresses the potential difference which exists at the point of equilibrium between a gelatin chloride solution contained in a collodion bag and an outside aqueous solution (without gelatin). The depressing effect of a neutral salt on the P.D. is similar to the depression of the osmotic pressure of the gelatin chloride solution by the same salt. 2. It is shown that this depression of the P.D. by the salt can be calculated with a fair degree of accuracy on the basis of Nernst's logarithmic formula on the assumption that the P.D. which exists at the point of equilibrium is due to the difference of the hydrogen ion concentration on the opposite sides of the membrane. 3. Since this difference of hydrogen ion concentration on both sides of the membrane is due to Donnan's membrane equilibrium this latter equilibrium must be the cause of the P.D. 4. A definite P.D. exists also between a solid block of gelatin chloride and the surrounding aqueous solution at the point of equilibrium and this P.D. is depressed in a similar way as the swelling of the gelatin chloride by the addition of neutral salts. It is shown that the P.D. can be calculated from the difference in the hydrogen ion concentration inside and outside the block of gelatin at equilibrium. 5. The influence of the hydrogen ion concentration on the P.D. of a gelatin chloride solution is similar to that of the hydrogen ion concentration on the osmotic pressure, swelling, and viscosity of gelatin solutions, and the same is true for the influence of the valency of the anion with which the gelatin is in combination. It is shown that in all these cases the P.D. which exists at equilibrium can be calculated with a fair degree of accuracy from the difference of the pH inside and outside the gelatin solution on the basis of Nernst's logarithmic formula by assuming that the difference in the concentration of hydrogen ions on both sides of the membrane determines the P.D. 6. The P.D. which exists at the boundary of a gelatin chloride solution and water at the point of equilibrium can also be calculated with a fair degree of accuracy by Nernst's logarithmic formula from the value pCl outside minus pCl inside. This proves that the equation x(2) = y ( y + z) is the correct expression for the Donnan membrane equilibrium when solutions of protein-acid salts with monovalent anion are separated by a collodion membrane from water. In this equation x is the concentration of the H ion (and the monovalent anion) in the water, y the concentration of the H ion and the monovalent anion of the free acid in the gelatin solution, and z the concentration of the anion in combination with the protein. 7. The similarity between the variation of P.D. and the variation of the osmotic pressure, swelling, and viscosity of gelatin, and the fact that the Donnan equilibrium determines the variation in P.D. raise the question whether or not the variations of the osmotic pressure, swelling, and viscosity are also determined by the Donnan equilibrium.

Glycine and its Neutral Salt Addition Compounds

Glycine and its Neutral Salt Addition Compounds

The relation of excised muscle to acids, salts, and bases

The observation that both acids and alkalies cause swelling in excised muscles, and that this swelling is suppressed by the addition of neutral salts, is no new one. The pernicious influence of acids on muscle is referred to as a commonplace by Ringer in 1883 (20, 21) and quantitative data of both acid and alkaline swelling are given by Loeb in 1897 (11). Nevertheless, the subject has never yet received systematic investigation at the hands of any one worker. The following record of experiments showing the behaviour of excised muscle in a range of solutions from decinormal alkali to decinormal acid is intended as a contribution towards filling this vacancy. An account of some preliminary experiments on the swelling of excised muscle has already been published (9). The method of work in the present case is precisely the same. The sterno-cutaneous muscle of the frog was used in all experiments, and the temperature was kept constant at 20°C. in a thermostat.