A Comparison Between the Dissociation of the Haemocyanins of Helix and Crustacea

1926 ◽  
Vol 4 (2) ◽  
pp. 203-214
Author(s):  
LANCELOT T. HOGBEN ◽  
KATHLEEN F. PINHEY
Keyword(s):  
Helix Pomatia ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Dissociation Curve ◽  
Hydrogen Ion Concentration ◽  
Alkaline Side ◽  
Order Of Magnitude ◽  
N Gram ◽  
Increasing Temperature ◽  
Critical Ph

1. The effect of increasing temperature upon the dissociation curve of Helix is similar qualitatively to that which has been recorded in the case of haemoglobin and crustacean haemocyanin. The value of Q per n gram molecules of oxygen is about 8000 calories. That is, it is of the same order of magnitude as the value for crustacean haemocyanin, but in all probability significantly less. 2. The effect of increase of hydrogen-ion concentration upon the haemocyanin of Helix pomatia is remarkably slight as compared with its effect on crustacean haemocyanin. At low tensions no effect is detectable. Comparing the 50 per cent. and 75 per cent. saturation points, it is seen, that, as with crustacean haemocyanin, increasing hydrogen-ion concentration at first diminishes, but beyond a certain point increases, affinity for oxygen. The curves obtained on the acid side of this point are not identical in shape with the curves obtained on the alkaline side. The significance of this fact in relation to previous observations on crustacean haemocyanin, and to Rona and Ÿllpo's experiments on haemoglobin, is discussed in the text. 3. The behaviour of the haemocyanin of Helix as compared with that of crustacean haemocyanin in relation to the presence of neutral chlorides of the alkaline and alkaline earth metals is even more different. In alkaline medium, the addition of neutral chlorides to the serum depresses the dissociation curve; at a point on the acid side of the critical pH referred to in section 2, addition of salts was not found to exert any detectable influence.

scholarly journals A Colorimetric Method for Studying the Dissociation of Oxyhæmocyanin suitable for Class Work

1925 ◽  
Vol 13 (4) ◽  
pp. 970-980 ◽  
Author(s):  
C. F. A. Pantin ◽  
Lancelot T. Hogben
Keyword(s):  
Marked Effect ◽  
Colorimetric Method ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Dissociation Curve ◽  
Hydrogen Ion Concentration ◽  
Laboratory Class ◽  
Wide Range ◽  
Increasing Temperature ◽  
Limits Of Error

1. A simple colorimetric method for plotting the dissociation curve of haemocyanin is indicated. The limits of error are within 5 per cent. The simplicity of the method commends it for laboratory class work.2. The effect of hydrogen ion concentration on the dissociation of the hsemocyanins of the crustacean Palinurus and the pulmonate Helix have been compared. In the snail change of hydrogen ion concentration over a wide range was not found to affect the dissociation of the hsemocyanin: in 'the crustacean there is a marked effect similar to that seen in the dissociation of hæmoglobin.3. The similarity of crustacean hsemocyanin to haemoglobin is also seen in that increasing temperature depresses the dissociation curve. The effects of certain salts upon haemocyanin. have also been recorded.

Some Observations on the Dissociation of Hæmocyanin by the Colorimetric Method

1926 ◽  
Vol 3 (3) ◽  
pp. 225-238
Author(s):  
LANCELOT T. HOGBEN
Keyword(s):  
Colorimetric Method ◽  
Hydrogen Ion ◽  
Mass Action ◽  
Ion Concentration ◽  
Effect Of Temperature ◽  
Heat Of Reaction ◽  
Dissociation Curve ◽  
Hydrogen Ion Concentration ◽  
Mass Action Law ◽  
N Gram

1. By means of the colorimetric method the effect of temperature, hydrogen ion concentration, and salinity upon the dissociation of the haæmocyanin of four species of decapod Crustacea (Maia, Cancer, Palinurus, and Homarus) has been studied. 2. Rise in temperature depresses the dissociation curve continuously between o° and 50° C. Reasons are given in favour of the conclusion that this behaviour is consonant with the applicability of the mass action law. On this understanding the heat of reaction between hæmocyanin and oxygen dissolved in the water phase in the case of Maia is of the order 9500 calories per n gram molecules of oxygen, n being defined as the least number of molecules of oxygen which can enter into the reaction. 3. In the case of all four crustaceans referred to above, the affinity for oxygen diminishes up to a point as the hydrogen ion concentration is increased : on further increasing the hydrogen ion concentration beyond a critical value for which the affinity of the serum for oxygen is minimal, the amount of oxygen taken up at low tensions increases and may surpass the values obtained for serum at normalpH. The similarity of this result with the observations of Rona and Ÿllpo on hæmoglobin is discussed. 4. On concentrating serum with neutral chlorides of the alakali and alkaline earth metals the dissociation curve is made steeper.

scholarly journals AMPHOTERIC COLLOIDS

1918 ◽  
Vol 1 (2) ◽  
pp. 237-254 ◽  
Author(s):  
Jacques Loeb
Keyword(s):  
Isoelectric Point ◽  
Water Solubility ◽  
Biological Significance ◽  
Volumetric Analysis ◽  
The Body ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Sharp Drop ◽  
Hydrogen Ion Concentration ◽  
Alkaline Side

1. It is shown by volumetric analysis that on the alkaline side from its isoelectric point gelatin combines with cations only, but not with anions; that on the more acid side from its isoelectric point it combines only with anions but not with cations; and that at the isoelectric point, pH = 4.7, it combines with neither anion nor cation. This confirms our statement made in a previous paper that gelatin can exist only as an anion on the alkaline side from its isoelectric point and only as a cation on the more acid side of its isoelectric point, and practically as neither anion nor cation at the isoelectric point. 2. Since at the isoelectric point gelatin (and probably amphoteric colloids generally) must give off any ion with which it was combined, the simplest method of obtaining amphoteric colloids approximately free from ionogenic impurities would seem to consist in bringing them to the hydrogen ion concentration characteristic of their isoelectric point (i.e., at which they migrate neither to the cathode nor anode of an electric field). 3. It is shown by volumetric analysis that when gelatin is in combination with a monovalent ion (Ag, Br, CNS), the curve representing the amount of ion-gelatin formed is approximately parallel to the curve for swelling, osmotic pressure, and viscosity. This fact proves that the influence of ions upon these properties is determined by the chemical or stoichiometrical and not by the "colloidal" condition of gelatin. 4. The sharp drop of these curves at the isoelectric point finds its explanation in an equal drop of the water solubility of pure gelatin, which is proved by the formation of a precipitate. It is not yet possible to state whether this drop of the solubility is merely due to lack of ionization of the gelatin or also to the formation of an insoluble tautomeric or polymeric compound of gelatin at the isoelectric point. 5. On account of this sudden drop slight changes in the hydrogen ion concentration have a considerably greater chemical and physical effect in the region of the isoelectric point than at some distance from this point. This fact may be of biological significance since a number of amphoteric colloids in the body seem to have their isoelectric point inside the range of the normal variation of the hydrogen ion concentration of blood, lymph, or cell sap. 6. Our experiments show that while a slight change in the hydrogen ion concentration increases the water solubility of gelatin near the isoelectric point, no increase in the solubility can be produced by treating gelatin at the isoelectric point with any other kind of monovalent or polyvalent ion; a fact apparently not in harmony with the adsorption theory of colloids, but in harmony with a chemical conception of proteins.

scholarly journals Interfacial tension and hydrogen-ion concentration

1931 ◽  
Vol 109 (760) ◽  
pp. 88-90 ◽  
Keyword(s):  
Interfacial Tension ◽  
Carboxylic Acids ◽  
Capric Acid ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Dissociation Curve ◽  
Weak Base ◽  
Hydrogen Ion Concentration ◽  
Long Chain ◽  
Hydrion Concentration

(1) Long chain carboxylic acids dissolved in benzene show regular changes in interfacial tension against aqueous "buffered" solutions as the hydrion concentration of these is altered. A fall in interfacial tension starts at p h 5·5 and extends over the range of 4·0 p h 9·3 approximately, tending to vanish at this point. The curve is not identical with a dissociation curve, though it extends over the same range of p h . For a given p h the results are identical for phosphate and glycine "buffered" solutions, and for all acids investigated, except capric acid(C 10 ), which shows an abnormality for phosphate. (2) Hexadecylamine shows similar changes, in the opposite sense between approximately the same p h range, which follow the dissociation curve of a weak base rather closely

scholarly journals AMPHOTERIC COLLOIDS

1918 ◽  
Vol 1 (1) ◽  
pp. 39-60 ◽  
Author(s):  
Jacques Loeb
Keyword(s):  
Physical Properties ◽  
Osmotic Pressure ◽  
Isoelectric Point ◽  
Alkali Treatment ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Neutral Salt ◽  
Sharp Drop ◽  
Hydrogen Ion Concentration ◽  
Alkaline Side

1. It has been shown in this paper that while non-ionized gelatin may exist in gelatin solutions on both sides of the isoelectric point (which lies for gelatin at a hydrogen ion concentration of CH = 2.10–5 or pH = 4.7), gelatin, when it ionizes, can only exist as an anion on the less acid side of its isoelectric point (pH > 4.7), as a cation only on the more acid side of its isoelectric point (pH < 4.7). At the isoelectric point gelatin can dissociate practically neither as anion nor as cation. 2. When gelatin has been transformed into sodium gelatinate by treating it for some time with M/32 NaOH, and when it is subsequently treated with HCl, the gelatin shows on the more acid side of the isoelectric point effects of the acid treatment only; while the effects of the alkali treatment disappear completely, showing that the negative gelatin ions formed by the previous treatment with alkali can no longer exist in a solution with a pH < 4.7. When gelatin is first treated with acid and afterwards with alkali on the alkaline side of the isoelectric point only the effects of the alkali treatment are noticeable. 3. On the acid side of the isoelectric point amphoteric electrolytes can only combine with the anions of neutral salts, on the less acid side of their isoelectric point only with cations; and at the isoelectric point neither with the anion nor cation of a neutral salt. This harmonizes with the statement made in the first paragraph, and the experimental results on the effect of neutral salts on gelatin published in the writer's previous papers. 4. The reason for this influence of the hydrogen ion concentration on the stability of the two forms of ionization possible for an amphoteric electrolyte is at present unknown. We might think of the possibility of changes in the configuration or constitution of the gelatin molecule whereby ionized gelatin can exist only as an anion on the alkaline side and as a cation on the acid side of its isoelectric point. 5. The literature of colloid chemistry contains numerous statements which if true would mean that the anions of neutral salts act on gelatin on the alkaline side of the isoelectric point, e.g. the alleged effect of the Hofmeister series of anions on the swelling and osmotic pressure of common gelatin in neutral solutions, and the statement that both ions of a neutral salt influence a protein simultaneously. The writer has shown in previous publications that these statements are contrary to fact and based on erroneous methods of work. Our present paper shows that these claims of colloid chemists are also theoretically impossible. 6. In addition to other physical properties the conductivity of gelatin previously treated with acids has been investigated and plotted, and it was found that this conductivity is a minimum in the region of the isoelectric point, thus confirming the conclusion that gelatin can apparently not exist in ionized condition at that point. The conductivity rises on either side of the isoelectric point, but not symmetrically for reasons given in the paper. It is shown that the curves for osmotic pressure, viscosity, swelling, and alcohol number run parallel to the curve of the conductivity of gelatin when the gelatin has been treated with acid, supporting the view that these physical properties are in this case mainly or exclusively a function of the degree of ionization of the gelatin or gelatin salt formed. It is pointed out, however, that certain constitutional factors, e.g. the valency of the ion in combination with the gelatin, may alter the physical properties of the gelatin (osmotic pressure, etc.) without apparently altering its conductivity. This point is still under investigation and will be further discussed in a following publication. 7. It is shown that the isoelectric point of an amphoteric electrolyte is not only a point where the physical properties of an ampholyte experience a sharp drop and become a minimum, but that it is also a turning point for the mode of chemical reactions of the ampholyte. It may turn out that this chemical influence of the isoelectric point upon life phenomena overshadows its physical influence. 8. These experiments suggest that the theory of amphoteric colloids is in its general features identical with the theory of inorganic hydroxides (e.g. aluminum hydroxide), whose behavior is adequately understood on the basis of the laws of general chemistry.

scholarly journals THE THERMOLABILITY OF COMPLEMENT, IN RELATION TO THE HYDROGEN ION CONCENTRATION

1921 ◽  
Vol 3 (6) ◽  
pp. 771-782
Author(s):  
Calvin B. Coulter
Keyword(s):  
Isoelectric Point ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Distilled Water ◽  
Hydrogen Ion Concentration ◽  
Albumin Fraction ◽  
Alkaline Side

1. The destruction which complement undergoes on being heated in dilution in distilled water is least at a reaction between pH 6.1 and 6.4. This depends upon the relative preservation of the midpiece function at this point. This reaction represents probably the isoelectric point of a compound of the euglobulin with some substance present also in serum. 2. During the process of thermoinactivation it is chiefly or entirely the ions of this euglobulin compound which react, and these combine or interact with substances contained in the pseudoglobulin and albumin fraction. 3. The behavior of the euglobulin is different in the anionic and in the cationic condition, since on the acid side of pH 6.1 to 6.4 the destruction by heat increases as rapidly with the acidity in the presence as in the absence of NaCl. On the alkaline side of this point the presence of NaCl protects complement from destruction because of the depression in the ionization of the euglobulin.

Digestion in Parasitic Nematodes. III. The Digestion of Proteins

1941 ◽  
Vol 19 (1-2) ◽  
pp. 47-58 ◽  
Author(s):  
W. P. Rogers
Keyword(s):  
Free Acid ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Parasitic Nematodes ◽  
Similar Amount ◽  
Hydrogen Ion Concentration ◽  
Alkaline Side ◽  
Relative Production ◽  
Blood Albumin ◽  
Substrate Proteins

Tryptic-like enzymes have been extracted from the intestines and intestinal contents of Ascarts lumbricoides and Strongylus edentatus. The action of these enzymes, in relation to hydrogen ion concentration, has been examined.The parasite trypsins resembled pancreatic trypsin in that the relative production of “free acid” and “formaldehyde acid” was similar, but though acting only on the alkaline side of the isoelectric points of the substrate proteins, optimum action on gelatin, blood-albumin and casein was obtained at pH 6·2.The amount of protease extracted from a given weight of S. edentatus tissue was far greater than that from a similar amount of A. lumbricoides. Thus Strongylus digested 4·9 to 8·3 times as much gelatin, 12·5 to 40·9 times as much casein and 2·5 to 5·2 times as much blood-albumin as Ascaris.Spectroscopic examination of the process of digestion of oxyhaemoglobin showed, first, the formation of reduced haemoglobin and then the formation of haematin. These changes took place most rapidly at higher hydrogen ion concentrations.

scholarly journals THE EQUILIBRIUM BETWEEN HEMOLYTIC SENSITIZER AND RED BLOOD CELLS IN RELATION TO THE HYDROGEN ION CONCENTRATION

1921 ◽  
Vol 3 (4) ◽  
pp. 513-521 ◽  
Author(s):  
Calvin B. Coulter
Keyword(s):  
Red Blood Cells ◽  
Isoelectric Point ◽  
Blood Cells ◽  
De Novo ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Free Medium ◽  
Hydrogen Ion Concentration ◽  
Alkaline Side ◽  
Basic Dissociation

1. In a salt-free medium the proportion of the total amount of hemolytic sensitizer present, combined with the homologous cells, reaches a maximum of almost 100 per cent at pH 5.3. On the alkaline side of this point the proportion combined diminishes with the alkalinity and reaches a minimum of approximately 5 per cent at pH 10. On the acid side of pH 5.3 the proportion combined diminishes with the acidity but somewhat less rapidly than for a corresponding increase in alkalinity. 2. The presence of NaCl greatly increases the proportion of sensitizer combined with cells at all reactions except those in the neighborhood of pH 5.3. At this point the combination of sensitizer with cells is independent of the presence of electrolyte. 3. The curves representing the proportion of sensitizer combined or free run almost exactly parallel, both when the sensitizer combines de novo and when it dissociates from combination; therefore, in constant volume, at a given hydrogen ion concentration, and at a given temperature, an equilibrium exists between the amount of sensitizer free and that combined with cells. 4. The combination of sensitizer and cells is related fundamentally to the isoelectric point of the sensitizer. 5. The dissociated ions of the sensitizer, formed either by its acid or its basic dissociation, do not unite with cells. Combination takes place only between the cells and the undissociated molecules of the sensitizer.

A Note on Haemerythrin

1927 ◽  
Vol 4 (4) ◽  
pp. 357-364
Author(s):  
GUY FREDERIC MARRIAN
Keyword(s):  
Absorption Spectra ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Small Range ◽  
Dissociation Curve ◽  
Purple Colour ◽  
Hydrogen Ion Concentration ◽  
Ion Concentrations

1. The effect of change of temperature on the dissociation curve of oxyhaemerythrin is shown. The heat of combination between haemerythrin and oxygen has been calculated to be 10,350 calories per gramme molecule of oxygen. 2. It has been shown that oxyhaemerythrin is only stable over a small range of pH. The pigment appears to be most stable at pH 8.0 and 9.0. Variation of hydrogen-ion concentration between pH 6.0 and pH 10.0 appears to have little effect on the dissociation curve of oxyhaemerythrin. 3. Oxyhaemerythrin can be converted to a yellow "methaemerythrin" by the action of oxidising agents. The change occurs spontaneously at slightly acid hydrogen-ion concentrations. 4. Attempts to show the presence of haem in the haemerythrin molecule have been unsuccessful. 5. The nature of the purple colour produced by the action of concentrated H2SO4 on a solution of oxyhaemerythrin is discussed. 6. Photographs of the absorption spectra of oxyhaemerythrin, methaemerythrin and the H2SO4 product of oxyhaemerythrin are shown.

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