The Origin, Partial Structure, and Properties of Hemoglobin A₁꜀

Citation

Holmquist, Walter Richard (1966) The Origin, Partial Structure, and Properties of Hemoglobin A₁꜀. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/3J9E-MW80. https://resolver.caltech.edu/CaltechETD:etd-09182002-134944

Abstract

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. Hemoglobin A(Ic) is a minor hemoglobin component of normal adult humans and comprises approximately 5% of the total hemoglobin. This thesis describes the in vitro biosynthesis of A(Ic) and the chemical properties and structure of this component and its degradation products. A(Ic) was found to be biosynthesized concurrently with hemoglobin A, which is the major component (80-90%) in normal adult hemoglobin. A(Ic) is thus a normal constituent of all red cells, irrespective of their physiological age. Chemically, A(Ic) is the condensation product--a Schiff base--between one molecule of hemoglobin A and one molecule of a ketone or aldehyde R==O. The point of linkage of R==O to hemoglobin A is the N-terminus of one of the two [beta] chains. Other than this, no difference has been found between the primary amino acid sequence of the [alpha] and [beta] chains of hemoglobin A(Ic) and A. The ketone or aldehyde R==O has a molecular weight of approximately 281, is not an aromatic aldehyde, is not a steroid, and does not contain phosphorus, carbohydrates or amino acids. Esterified nonketo acyl groups of less than five carbon atoms are absent. It is probable, but not certain, that R==O does not contain nitrogen and that it does not contain any free carboxyl groups. Methods are described for isolating A(Ic) as well as smaller peptides which contain the blocking group R such as R=val-his. The use and construction of a large (10 x 100-cm) chromatographic column for the preparative isolation of minor hemoglobin components is described. This column is rather unique and should find applications in the isolation of other biological compounds. Certain other isolation procedures which are described in the thesis, such as the purification of peptides on cellulose phosphate, have not been previously described. Finally several miscellaneous theoretical aspects of the thesis are of interest. These include the theory of self-hybridization experiments, a theoretical treatment of protein biosynthesis which includes a method for correcting the experimental data for nonconstant ribosomal activity and for interconversions of the protein of interest to other proteins during the biosynthesis. A practical method for calculating ionization constants from paper electrophoretic data is also given. Photographic materials on pp. 25, and 46 are essential and will not reproduce clearly on Xerox copies. Photographic copies should be ordered.

Thesis Files