T HE ASSOCIATION of congenital nonspherocytic hemolytic anemia with the presence of certain unstable hemoglobins has been recognized in numerous patients.1 The instability of these hemoglobins has been manifested by precipitation on heating in vitro and by the formation of Heinz bodies with premature destruction of erythrocytes in vivo. The molecular basis for the instability of certain of thes...

Previous studies suggested that y87 Gln in hemoglobin (Hb) F is an important site for promoting inhibition of Hb S (cy#: polymerization by H b F. We engineered and isolated the double mutant ) using a yeast expression system and characterized polymerization properties of this modified tetramer in an effort to clarify the role of Gln at position 87 in inhibiting H b S polymerization. Electrop...

The electron transfer properties of horse heart hemoglobin are compared using a hydrophilic indium tin oxide electrode and a dilaurydimethylammonium bromide (DDAB) polymer modified PG electrodes. A clear, stable and quasi-reversible redox curve of hemoglobin (Hb) was obtained in the absence of electron transfer mediators or promoters. The formal redox potential of -0.17 vs. Ag/AgCl of Hb was de...

BACKGROUND Thalassemia and hemoglobinopathies are inherited red blood cell disorders found worldwide. Hemoglobin (Hb) E disorder is one of the hemoglobinopathies known to have the high prevalence in South East Asia. Most of transfusion-dependent thalassemias were genotypically compound heterozygous Hb E/ β-thalassemia. In Malaysia, the national screening program for thalassemia was implemented ...

Symbiotic dinoflagellates are unicellular photosynthetic algae that live in mutualistic symbioses with many marine organisms. Within the transcriptome of coral endosymbionts Symbiodinium sp. (type C3), we discovered the sequences of two novel and highly polymorphic hemoglobin-like genes and proposed their 3D protein structures. At the protein level, four isoforms shared between 87 and 97% seque...

We found that deoxy Hb A aggregated or formed gels with a clear exhibition of a delay time when a solution of deoxy Hb A with a concentration of 120% of its solubility was incubated at 30°C. Since the solubility of deoxy Hb A is much higher than that of deoxy Hb S, this condition was created by increasing the phosphate concentration. The length of the delay and aggregation times and the amounts...

BACKGROUND A beta-hemoglobin variant (beta 126 (H4) Val-->Gly) was reported from Thailand and Naples (Southern Italy) as Hb Dhonburi (1) and Hb Neapolis (2), respectively. This abnormal hemoglobin, resulting from a valine to glycine substitution in the contact region between alpha and beta subunits, gives rise to instability at non-physiological conditions. However, it was difficult to distingu...

Redundant TonB systems which function in iron transport from TonB-dependent ligands have recently been identified in several gram-negative bacteria. We demonstrate here that in addition to the previously described tonB locus, an alternative system exists for the utilization of iron from hemoglobin, transferrin, or lactoferrin in Neisseria meningitidis and Neisseria gonorrhoeae. Following incuba...

Hemoglobin variants having electrophoretic mobility more rapid than that of HbA were identified in combination with sickle hemoglobin in two patients at the Cook County Hospital. Neither individual had symptomatic hematologic disease. In one patient, the rapidly migrating hemoglobin had the amino acid substitution characteristic of Hb Tacoma (beta-40 arg leads to ser), a mildly unstable variant...

We have previously shown that coculture of human embryonic stem cells (hESCs) for 14 days with immortalized fetal hepatocytes yields CD34(+) cells that can be expanded in serum-free liquid culture into large numbers of megaloblastic nucleated erythroblasts resembling yolk sac-derived cells. We show here that these primitive erythroblasts undergo a switch in hemoglobin (Hb) composition during la...