Chemical Characterization and Subunit Hybridization of Human Hemoglobin H and Associated Compounds^*

Abstract

Two abnormal hemoglobin components have been detected in association with thalassemiahemoglobin H disease. These components, as well as the major hemoglobin component, have been chemically characterized by determination of the amino acid composition, N-terminal amino acid sequence, tryptic peptide patterns, sedimentation coefficients, and subunit hybridization. The abnormal component in larger amount has a subunit formula of /34; the abnormal component in smaller amount has a subunit formula of 74. The major hemoglobin component could not be distinguished chemically from normal hemoglobin A. Subunit hybridization studies of hemoglobins indicate that the affinities of the various subunits for one another are not equal. Human hemoglobin H was first reported by Rigas et al. (1955) and was also observed independently by Gouttas et al. (1955) and by Motulsky (1956) about the * Contribution No. 2961 from the Division of Chemistry and Chemical Engineering.

An Unusual Hemoglobin Anomaly and Its Relation to α-Thalassemia and Hemoglobin-H Disease

“…Among these reports is one of a Chinese family (3,4) in which the propositus, a girl, had Hb-H disease as manifested by the presence of Hb-H and Hb-Bart's (or Y4). These hemoglobins were characterized by chemical studies (5). Observations on family members were consistent with the usual finding in relatives of patients with Hb--H disease, namely, that one parent is apparently normal whereas the other has a thalassemia trait (see 6-9 for summaries and references).…”

“…1). The original propositus, sister P. T., described in the previous studies (3)(4)(5) had died at the age of 6 yr. On four occasions, 10-50 ml of blood was collected from S. T. in acid-citrate dextrose solution and transported in ice by air from Los Angeles to Augusta; experiments usually started within 24 hr after the blood was collected. Smaller samples (10 ml) were collected in EDTA from the other members of the family.…”

“…The girl, now deceased, was about 4 yr old at the time of the study and would normally have reached hematological adulthood. However, in most reported instances, Hb-Bart's either does not accompany Hb-H (for example 1,5) or is present only in traces in the adult. Recently, there has been an opportunity to reinvestigate this Chinese family.…”

“…In retrospect, the manifestation of Received for publication 19 January 1971 and revised form 8 March 1971. Hb-H disease in this family has characteristics which make it unusual among reported occurrences of Hb-H disease. The propositus had about 15% of Hb-H and 5-10% of Hb-Bart's (5). A significant fact is the presence of an appreciable amount of Hb-Bart's.…”

Quantitative Deficiency of Chain-Specific Globin Messenger Ribonucleic Acids in the Thalassemia Syndromes

“…When there is some synthesis of the affected globin chain, analysis of its peptides reveals no evidence of an aminoacid substitution (6)(7)(8), nor is there evidence of synthesis of incomplete globin chains where there is total absence of the globin chain (9). There is a great deal of evidence, however, that the genes for a and f thalassemia are closely linked to the genes for the structural loci of the a and f globin chains, respectively (1).…”