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R W Noble

Publications and source records attributed to R W Noble.

At least 73 records · Page 4Linked to original sources
PubMed1975

Ligand binding properties of hemoglobin 3 of the trout, Salmo gairdneri. The occurrence of an acid Bohr effect in the absence of heme-heme interaction.

The four components of hemoglobin from the rainbow trout (Salmo gairdneri) have been isolated. The oxygen affinities of the first two components eluted from the DEAE-cellulose column have much smaller pH dependencies than the last two components. These components have very low O2 affinities at low pH. The effect of pH on the equilibrium and kinetics of ligand binding to the third fraction, the pH-dependent component present in greatest amounts, has been studied. Measurements of ligand binding equilibria demonstrate the presence of both an alkaline and an acid Bohr effect. In the region of the alkaline Bohr effect the value of n in the Hill equation is a function of ligand affinity. For CO binding n decreases as the pH is decreased until at pH 6, the minimum ligand affinity is reached. At this pH there is also a complete loss of cooperative ligand binding. Decreasing the pH further results in an increase of ligand affinity, but this acid Bohr effect is not associated with a reappearance of cooperativity. This suggests that Fraction 3 of S. gairdneri is frozen in the low affinity, deoxygenated conformation at low pH and that the quaternary structure does not change even when fully liganded. However, the properties of the low affinity conformation of this hemoglobin are pH-dependent.

Animals↗
PubMed1975

Restriction of heterogeneity of goat antibodies specific for human hemoglobin SS.

Previously, we had reported the isolation of an antibody population (termed antiVal antibody) specific for the site of difference between human hemoglobin S(HbS)(beta-6Val) and hemoglobin A-1(BbA)(beta-6 glu). This population has a stoichiometry of reaction of unity in combining with HbS (alpha-beta-dimer) and shows no reaction with HbA. The combination of antiVal Fab fragments with HbS was found to be kinetically homogeneous and had a second order rate constant of 0.58 times 10-6M-1 sec-1 at 20 degrees C. In this report we have studied other properties of the antiVal population. These antibodies are restricted to only one of the two heavy chain subclasses of goat IgG. Electrophoresis experiments indicated that the antiVal population is much less polydisperse than the total antiHbS response. A method was developed to measure the dissociation kinetics of antiVal-HbS complexes. This dissociation was also found to be kinetically homogeneous and could be described by a single first order rate constant of 2.67 times 10-5 sec-1 at 20 degrees C. With homogeneous association and dissociation rate constants, an affinity constant of 2.1 times 10-10M-1 at 20 degrees C was calculated. It appears, then, that this population of antibodies, which are directed toward a single antigenic determinant on a globular protein, exhibit limited structural heterogeneity associated with great functional homogeneity.

Absorption↗