Helen M. Ranney

An increase in a minor hemoglobin component closely resembling hemoglobin AIc in which one or more hexoses are bound to the beta-polypeptide chains was observed in a previous study of diabetic patients. In the present study the proportions of chromatographically rapid (fast) minor components of hemoglobin, 75 to 80 per cent of which is accounted for by hemoglobin AIc, were quantified by a modified Chromatographic method in 20 normal and 100 diabetic subjects. Mean values for the proportions of fast hemoglobin components (glycohemoglobin) in diabetes showed a nearly twofold increase over values found in normal subjects. The increased proportions of these fast components did not appear to be related to the age of the patients, or to the duration, therapy or complications of diabetes. The increase in proportions of glycohemoglobin in diabetes mellitus appears to be another example of increased glycoproteins in this disorder.

The bimane fluorescent labels, monobromobimane, dibromobimane, and monobromotrimethylammoniobimane, are derivatives of syn-9,10-dioxabimane:1,5-diazabicyclo[3.3.0]octa-3,6-diene-2,8-dione. They efficiently label hemoglobin (reactive thiol groups), membrane proteins, and glutathione of normal human red cells under physiological conditions. Monobromobimane and dibromobimane are effective on intact cells while red cell membranes may be impermeable to the positively charged monobromotrimethylammoniobimane, the latter being effective only on lysed cells. These bimane labels provide a class of labeling agents that may have wide applicability in biological materials.

Hemoglobin quenching of the fluorescence intensity of 12-(9-anthroyl)stearic acid (AS) embedded in the red blood cell membrane occurs through an energy transfer mechanism and can be used to measure the binding of hemoglobin to the membrane. The binding of hemoglobin to red cell membranes was found to be reversible and electrostatic in nature. Using a theory of energy transfer based on Förster formulation, the quantitative data for the binding were derived. The number of binding sites was found to be 1.4 +/- 0.2 X 10(6) molecules per cell and the binding constant was 0.85 X 10(8) M-1.

Abstract A new sickling hemoglobin variant designated hemoglobin Charlem (Hb Ch) migrated slightly anodally to the position of hemoglobin C on electrophoresis at pH 8.6, and has been shown to have the structure αa2 β6 glu → val, 73 asp → asn2. Hemoglobin Ch comprised 40% of the hemoglobin in individuals of two generations of an American Negro family and is the first instance in which two amino acid substitutions in a single polypeptide chain have been defined in a human hemoglobin variant. Hemoglobin Ch appeared not to differ significantly from Hb A in its oxygen equilibria, ultraviolet spectra of the oxy and deoxy forms, and titratable sulfhydryl groups. Probably by virtue of its β6 val substitution, Hb Ch shared with Hb S (αa2 β6 glu → val2) the properties of erythrocyte sickling and relative insolubility and gelation of the deoxyhemoglobin. However, gelation experiments suggested that the β73 asn substitution resulted in a decrease in the intermolecular interactions of deoxyhemoglobin Ch as compared with deoxyhemoglobin S, and implied conformational differences between the two deoxyhemoglobins.