scholarly journals THE METAMORPHOSIS OF HEMOGLOBIN IN THE BULLFROG

1951 ◽  
Vol 35 (1) ◽  
pp. 23-40 ◽  
Author(s):  
Austen Riggs
Keyword(s):  
Molecular Weight ◽  
Oxygen Affinity ◽  
Hill’S Equation ◽  
Effect Of Ph ◽  
Oxygen Equilibrium ◽  
Hill's Equation ◽  
Adult Hemoglobin

1. Tadpole and adult hemoglobin do not differ significantly in molecular weight. The molecular weight of both is in the neighborhood of 68,000. 2. Heme-heme interaction as measured by the value of n in Hill's equation is virtually the same—about 2.8—in both tadpole and adult. 3. There appears to be no significant effect of pH upon the oxygen equilibrium of tadpole hemoglobin, in contrast to large Bohr and reverse Bohr effects in the adult. This is taken to mean that during metamorphosis acid groups of globin become sensitive to the oxygenation of heme by some change in the mode of linkage between heme and globin. 4. The oxygen affinity of tadpole hemoglobin is about seven times as great as that of the adult at pH 6 and twice as great at pH 9.

scholarly journals THE EFFECT OF FORMALDEHYDE ON THE OXYGEN EQUILIBRIUM OF HEMOGLOBIN

1954 ◽  
Vol 37 (6) ◽  
pp. 775-780 ◽  
Author(s):  
Karl F. Guthe
Keyword(s):  
Oxygen Pressure ◽  
Oxygen Affinity ◽  
Sulfhydryl Groups ◽  
Human Hemoglobin ◽  
Hill’S Equation ◽  
Oxygen Equilibrium ◽  
Hill's Equation ◽  
Hemoglobin Molecule

1. When formaldehyde (0.10 M) is added to solutions of human hemoglobin, the oxygen affinity of the hemoglobin increases considerably (more than tenfold near pH 7). The interaction between hemes of the same hemoglobin molecule decreases, as shown by a drop in the value of n in Hill's equation from 2.9 to 1.5 or less. 2. In the presence of formaldehyde, both n and the oxygen pressure for half-saturation fall gradually as the pH rises in the range from pH 6.2 to 7.2. 3. Some of the effect of formaldehyde on the oxygen equilibrium may be due to combination with sulfhydryl groups of the protein, but nitrogenous groups are probably also involved.

scholarly journals SULFHYDRYL GROUPS AND THE INTERACTION BETWEEN THE HEMES IN HEMOGLOBIN

1952 ◽  
Vol 36 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Austen F. Riggs
Keyword(s):  
Oxygen Affinity ◽  
Sulfhydryl Groups ◽  
Hemoglobin Solution ◽  
Hill’S Equation ◽  
Sulfhydryl Reagent ◽  
Hill's Equation

1. Dialysis of a hemoglobin solution against slightly alkaline buffer (pH 8.68) causes a decrease in heme-heme interaction. The value of n in Hill's equation drops from 2.9 to 2.0, while the oxygen affinity increases slightly. Addition of glutathione largely reverses the effects of dialysis (n rises from 2.0 to 2.5 to 2.6). 2. Addition of the sulfhydryl reagent, p-chloromercuribenzoate (1.8 x 10–3 M), results in a large though not complete blocking of heme-heme interaction. The value of n drops from 2.9 to 1.4. This effect is largely reversed with glutathione (n rises to 2.6).

scholarly journals THE OXYGEN EQUILIBRIUM OF THE HEMOGLOBIN OF THE EEL, ANGUILLA ROSTRATA

1951 ◽  
Vol 35 (1) ◽  
pp. 41-44 ◽  
Author(s):  
Austen Riggs
Keyword(s):  
Hill Equation ◽  
Anguilla Rostrata ◽  
Hill’S Equation ◽  
Oxygen Equilibrium ◽  
Equilibrium Function ◽  
Hill's Equation ◽  
The Hill

Kawamoto had reported that eel hemoglobin has a hyperbolic oxygen equilibrium function, with n in the Hill equation equal to 1. On the basis of Kawamoto's data and with new measurements, it is shown that the equilibrium function is in fact S-shaped, as in most other vertebrates, and n in Hill's equation equals 1.8.

On the solution of Hill's equation using Milne's method

1991 ◽  
Vol 24 (9) ◽  
pp. 2069-2081 ◽  
Author(s):  
J A Nunez ◽  
F Bensch ◽  
H J Korsch
Keyword(s):  
Hill’S Equation ◽  
Hill's Equation

Vibration and Stability of an Elastic Beam Subjected to a Periodic Axial Load With Time-Dependent Displacement Excitation at Both Ends

1991 ◽  
Author(s):  
Xiao-Feng Wu ◽  
Adnan Akay
Keyword(s):  
Axial Load ◽  
Perturbation Technique ◽  
Harmonic Balance Method ◽  
Elastic Beam ◽  
Time Dependent ◽  
Transverse Load ◽  
Order Partial Differential Equation ◽  
Weighted Residual Method ◽  
Hill’S Equation ◽  
Hill's Equation

Abstract This paper concerns the transverse vibrations and stabilities of an elastic beam simultaneously subjected to a periodic axial load, a distributed transverse load, and time-dependent displacement excitations at both ends. The equation of motion derived from Bernoulli-Euler beam theory is a fourth-order partial differential equation with periodic coefficients. To obtain approximate solutions, the method of assumed-modes is used. The unknown time-dependent function in the assumed-modes method is determined by a generalized inhomogeneous Hill’s equation. The instability regions possessed by this generalized Hill’s equation are obtained by both the perturbation technique up to the second order and the harmonic balance method. The dynamic response and the corresponding spectrum of the transversely oscillating elastic beam are calculated by the weighted-residual method.

Red cell oxygen affinity in fetal sheep: role of 2,3-DPG and adult hemoglobin

1978 ◽  
Vol 45 (1) ◽  
pp. 7-10 ◽  
Author(s):  
H. Bard ◽  
J. C. Fouron ◽  
J. E. Robillard ◽  
A. Cornet ◽  
M. A. Soukini
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Oxygen Affinity ◽  
Fetal Life ◽  
Red Cell ◽  
Adult Type ◽  
Fetal Sheep ◽  
Adult Hemoglobin ◽  
Relationship Of

Studies were carried out during fetal life in sheep to determine the relationship of 2,3-diphosphoglycerate (DPG), the intracellular red cell and extracellular pH, and the switchover to adult hemoglobin synthesis in regulating the position of the fetal red cell oxygen-affinity curve in utero. Adult hemoglobin first appeared near 120 days of gestation. The mean oxygen tension at which hemoglobin is half saturated (P50) prior to 120 days of gestation remained constant at 13.9 +/- 0.3 (SD) Torr and then increased gradually as gestation continued, reaching 19 Torr at term. During the interval of fetal life studied, the level of DPG was 4.43 +/- 1.63 (SD) micromol/g Hb and the deltapH between plasma and red blood cells was 0.227 +/- 0.038 (SD); neither was affected by gestational age. The decrease in the red cell oxygen affinity after 120 days of gestation ocrrelated with the amount of adult hemoglobin present in the fetus (r = 0.78; P less than 0.001). This decrease can be attributed only to the amount of the adult-type hemoglobin present, and not to DPG, or to changes in the deltapH between plasma and red blood cells, because both remained stable during the last trimester.

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