Hemoglobin deoxyhemoglobin

Human normal adult hemoglobin Deoxyhemoglobin the heme iron atoms are in the high-spin ferrous state with four unpaired electrons per heme iron... 

Although algorithms are often merely referred to peripherally, in an article by Piantadosi et al., the algorithms are the main topic of discussion [163]. Using a half dozen research papers (by other workers) as examples, the authors discuss the approaches used in NIR, citing both the hardware and the software. Most of the practical applications were on blood and the analytes were hemoglobin, deoxyhemoglobin, etc. 

The binding of oxygen to the deoxy form of hemoglobin (deoxyhemoglobin) causes a reduction in diameter of the iron atom which can then relax into the plane of the porphyrin ring. This motion is transferred to the polypeptide through the proximal histidine and eventually causes sliding of the subunits across one an-... 

A piece of equipment, developed to measure oxygen content, was produced by the Centre for Biomedical Technology in Australia [41]. It consisted of five 1W lasers at wavelengths of 780, 800, 830, 850, and 980 nm and used a photodiode receiver. It used the hemoglobin/deoxyhemoglobin absorbance differences and measured the SO2 content of the blood as well. 

Fig. 2. Reaction of diphosphoglycerate (2,3-DPG) and deoxyhemoglobin. The molecule fits into the central cavity of hemoglobin and forms salt bridges with valine NA(I)p, histidines NA2(2)p, H2I(I43)p, and lysine EF6(82)p. A, E, and E correspond to specific hemoglobin hehces and NA is the sequence...

Figure 6-9. The Bohr effect. Carbon dioxide generated in peripheral tissues combines with water to form carbonic acid, which dissociates into protons and bicarbonate ions. Deoxyhemoglobin acts as a buffer by binding protons and delivering them to the lungs. In the lungs, the uptake of oxygen by hemoglobin releases protons that combine with bicarbonate ion, forming carbonic acid, which when dehydrated by carbonic anhydrase becomes carbon dioxide, which then is exhaled.

Figure 6-11. Representation of the sticky patch (A) on hemoglobin S and its "receptor" (A) on deoxyhemoglobin A and deoxyhemoglobin S. The complementary surfaces allow deoxyhemoglobin S to polymerize into a fibrous structure, but the presence of deoxyhemoglobin A will terminate the polymerization by failing to provide sticky patches. (Modified and reproduced, with permission, from Stryer L Biochemistry, 4th ed. Freeman, 1995.)...

Deoxyhemoglobin can bind more carbon dioxide than oxygenated hemoglobin. Therefore, unloading of oxygen in the tissues facilitates loading... 

Hemoglobin is directly measured and is an independent and continuous variable However, and probably because at any one time a number of forms and conformations (oxyhemoglobin, deoxyhemoglobin, methemoglobin, etc.) of hemoglobin are actually present the distribution seen is not typically a normal one, but rather may be a multimodal one. Here a nonparametric technique such as the Wilcoxon or multiple rank-sum is called for. 

Subunit contacts need to be relatively extensive and stable if they are to ensure subunit association in the absence of a covalent link. However, in some cases a subunit contact can shift back and forth between two different stable positions, as has been demonstrated for oxy- versus deoxyhemoglobin (Perutz, 1970). Allosteric control can then be exerted by any factors which either affect the local conformation or bind between the subunits. A less elegant but even more extreme example is lamprey hemoglobin, which dissociates altogether in the oxy form (Hendrickson and Love, 1971). 

Four of the six coordination sites of the iron in hemoglobin are occupied by the nitrogen atoms of the pyrrol rings, and another is occupied by a histidine residue of the globin (the proximal histidine). The iron s sixth site is coordinated with oxygen in oxyhemoglobin and with H2O in deoxyhemoglobin. 

A nonbiological reductant (8204 ) that has proven to be of immense value in converting uncomplexed and porphyrin-bound Fe(III) to the +2 oxidation state with the concomitant formation of two molecules of SO2 gas. Dithionite also reacts with heme-bound oxygen to produce deoxyhemoglobin, and treatment of intact red blood cells with dithionite can induce sickling in cells containing hemoglobin S. Dithionite also reduces NAD+ to NADH. 

Some patients with erythrocytosis (excess RBCs) have a mutation that converts a lysine to alanine at amino acid 82 in the 3 subunit of hemoglobin. This particular lysine normally protrudes into the central cavity of deoxyhemoglobin, where it participates in binding 2,3-bisphosphoglycerate (BPG). 

FIGURE 5-9 Some ion pairs that stabilize the T state of deoxyhemoglobin. (a) A close-up view of a portion of a deoxyhemoglobin molecule in theT state (PDB ID 1HGA). Interactions between the ion pairs His HC3 and Asp FG1 of the 0 subunit (blue) and between Lys C5 of the a subunit (gray) and His HC3 (its cr-carboxyl group) of the )3 subunit are shown with dashed lines. (Recall that HC3 is the carboxyl-terminal residue of the 0 subunit.) (b) The interactions between these ion pairs, and between others not shown in (a), are schematized in this representation of the extended polypeptide chains of hemoglobin. 

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