Immobilized hemoproteins

New developments in protein isolation, purification, and characterization

The most significant advancements in techniques and methods for protein purification and analysis have been made in liquid chromatography and in electrophoresis. In the area of chromatography, adsorbents based on new affinity principles have been prepared. New packing materials have facilitated the rapid progress of high-performance techniques. A great many new techniques in the field of electrophoresis have emerged. On an analytical scale, electrophoretic methods in two dimensions or in capillaries are unsurpassed in resolution power. Development of techniques for protein transfer between different media is a prerequisite for a full exploitation of the new methods. Modern techniques for analysis of submicrogram quantities facilitate the separation, detection, and characterization of complex protein mixtures.

Biospecific interactions: their quantitative characterization and use for solute purification

Biospecificity is due largely to the formation and dissociation of non-covalent complexes between small molecules and macromolecules, or between two macromolecules. The first part of this review is concerned with the use of such biospecificity in the fractionation and identification of solutes. Major emphasis is given to affinity chromatography, especially in regard to the practical considerations inherent in an experimental situation and to the wide range of specific interactions that can be utilized. The second part of the review considers the quantitative characterization of biospecific complex formation. The merits of frontal gel chromatography, electrophoretic methods and affinity chromatography are discussed, and special consideration is given to the effects of ligand and/or acceptor multivalency because of its relevance to many biospecific interactions. Finally attention is drawn to the feasibility of employing quantitative affinity chromatographic theory for the determination of association constants for antigen-antibody systems by radioimmunoassay and enzyme-linked immunosorbent assay techniques.

Properties of human hemoglobin immobilized on Sepharose 4B

This paper reports the properties of human hemoglobin covalently bound to Sepharose 4B both in 'high-affinity' and 'low-affinity' conformations. The results suggest that the coupling reaction is strongly affected by the conformational changes linked to oxygenation of the protein. The rate and the extent of the reaction are different for the oxy and deoxyderivatives, probably due to the change in reactivity of the amino groups in the liganded and unliganded tetramer. The data on the equilibrium which is established between matrix-bound and soluble subunits, measured by the 'subunit-exchange chromatography', indicate that the system displays a minimal heterogeneity when hemoglobin is coupled to the gel in the deoxy state at intermediate protein concentration and pH 8. Maxtrix-bound hemoglobin is characterized by a higher oxygen affinity and by decreased homotropic and heterotropic interactions with respect to hemoglobin in solution, but the changes depend strongly on the conditions used in the coupling procedure.