Circular dichroism and difference ultraviolet visible spectra were obtained for cobalt hemoglobin derivatives. At 287 nm the ellipticity difference between the oxy- and deoxycobaltohemoglobin is about one-half as great as that for the native proteins indicating smaller quaternary conformational changes for the former. Deoxygenation increases the Soret rotational strengths of both iron and cobal...

Hemoglobins are ubiquitous in nature and among the best-characterized proteins. Genetics has revealed crucial roles for human hemoglobins, but similar data are lacking for plants. Plants contain symbiotic and nonsymbiotic hemoglobins; the former are thought to be important for symbiotic nitrogen fixation (SNF). In legumes, SNF occurs in specialized organs, called nodules, which contain millions...

Hemoglobin is a conjugated protein composed of heme prosthetic groups united to polypeptide chains. The structure, four heme groups associated with four polypeptide chains, seems to be similar for all mammalian hemoglobins (1). Usually the polypeptide chains appear in two forms, which in adults are called a and @ chains. Homology occurs among the polypeptide chains of hemoglobins partially beca...

Hagfish hemoglobin (Hb) is considered to represent a transition stage between invertebrate and vertebrate hemoglobins. The Hb system of Myxine glutinosa consists of three monomeric hemoglobins, which upon deoxygenation associate to form primarily heterodimers and heterotetramers. Myxine glutinosa is an osmoconformer, whose red blood cells show the exceptional ability to swell and remain swollen...

The clinical utility of glycated hemoglobin measurements in renal failure is controversial, given numerous earlier studies showing no correlation between glycated hemoglobin and other indicators of blood glucose control in uremic subjects. This problem is attributable, in part, to analytical interferences from carbamylated hemoglobins. We report use of a specific affinity method to measure glyc...

It is well established that hemoglobin resulting from red cell lysis binds to haptoglobin in plasma to form a complex. The increased molecular size precludes its filtration by the kidneys, redirecting it toward hepatocellular entry. Chemically cross-linked hemoglobins are designed to be resistant to renal excretion, even in the absence of haptoglobin. The manner in which binding to haptoglobin ...

Blood was drawn from 10 fasted, healthy volunteers and stored under standard blood bank conditions in citrate-phosphate-dextrose-adenine (CPDA-1). Blood was sampled before storage (Day 0) and on Days 5, 12, 19, 26, and 35. Laboratory testing for glucose, HbAla + b, HbAlc, pyruvic acid, lactic acid, adenosine triphosphate (ATP), 2, 3-diphosphoglycerate (2,3DPG), plasma free hemoglobin (Hb) and p...

Explants of normal mouse embryonic tissues and disaggregated embryonic single cells were cultured in vitro to study the erythropoietic progenitor cells present during embryonic development. The results indicate that there are two populations of erythropoietic progenitor cells committed to different hemoglobin synthetic programs. These progenitor cells are present at an early gestational stage p...

A group of single-domain proteins in Bacteria similar to thermoglobin, an oxygen-avid hemoglobin representative of the ancestral form, reveals the primordial structure, function, and evolvability of the family. Conserved residues at specific positions function to bind ligand or participate in hydrophobic packing of the protein core during protein folding. A potential hydrogen bond network consi...

Two hemoglobins with cysteine residues highly reactive toward electrophiles have been identified and characterized. Cys-125beta of guinea pig hemoglobin has a low pK(a) and forms conjugates with electrophiles more quickly than glutathione and several orders of magnitude more quickly than other protein thiols. This cysteine is capable of intercepting benzoquinone, a known carcinogenic metabolite...