Haemoglobin HbS

Jones, R. T. Koler, R. D. and Stocklen, Z. "Multiple Alpha Chain Loci for Human Haemoglobins Hb J-Buda and Hb G-Pest". Nature (1972), 47. 

Amadori-type early glycosylation products (Brownlee et /., 1988). Protein that has been glycated in vitro is con-formationally altered. For example, the amount of early glycosylation products in vivo in diabetics, whether on haemoglobin (Hb) or basement membrane, increases when blood glucose levels are normalized by treatment. 

The pulse oximeter is a non-invasive device used to monitor the percentage saturation of haemoglobin (Hb) with oxygen (Spo2). The underlying physical principle that allows this calculation to take place is that infrared light is absorbed to different degrees by the oxy and deoxy forms of Hb. 

Haemoglobin (Hb) is not strictly an enzyme, since it does not catalyse directly any specific reaction. Its function is the transport of 02 from the lungs to the tissues of the mammalian body, where organic substrates are oxidised exothermically to COz and water. Hb is classified as a metalloprotein, i.e. a protein which contains and utilises atoms of low electronegativity. 

The mode of 02 coordination was for some time a subject of controversy. It now seems settled that the ligand molecule is bonded via one O atom, with an Fe-O-O angle of c. 120°. This is consistent with the prediction of a rather crude VB description of the 02 molecule, which allocates two lone pairs to each atom the valence state of O is (sp2)2(sp2)2(sp2)1(p)1. This description is inconsistent with the observed paramagnetism of 02 (which can readily be explained in terms of MO theory). However, oxygenated haemoglobin Hb.402 is diamagnetic and we may fairly describe the Fe-0 bond in terms of a filled sp2 hybrid donor orbital from the O atom. 

The oxygen-binding curves for myoglobin(Mb) and haemoglobin(Hb), showing also the pH-dependence(Bohr effect). 

Thus, for haemoglobin (Hb) the oxygen binding curves are sigmoidal as is shown in the above figure. The fact that n exceeds the unit can be ascribed physically to the fact that attachment of 02 to one haem group increases the binding constant for the next 02, which in turn increases the constant for the next one and so... 

Immobilized haemoglobin (Hb) was applied by Liu and co-authors (Liu et al. 2006) to the dehalogenation of haloethanes (hexachloroethane, pentachloro-ethane, tetrachloroethane, etc.). The observed fast electron-transfer reactions observed in aqueous-organic solvents are promising for the detection of the... 

Figure 3.11 Investigation of abnormal haemoglobin (HbS). Part B figures reproduced from the Encyclopaedia Britannica online (www.britannica.com).

Haemoglobin (Hb), functions physiologically in the storage and transport of molecular oxygen in mammalian blood. The molecule is nearly spherical with... 

Figure 3.7 The / subunit of the haemoglobin (Hb) tetramer. The iron porphyrin embedded in the molecule is flanked on each side by the proximal and distal histidines. The Hb structure is dominated by a-helices. From Perutz (1970) reprinted with permission from Nature 228, 726-37 fig 1, copyright 1970 Macmillan Magazines Ltd.

Case study Refinement of a partially oxygenated T (tense) state human haemoglobin (Hb) at 1.5 A resolution (Waller and... 

Microtubular haemoglobin has been observed in erythrocytes in sickle cell anaemia. After deoxygenation and addition of thermal energy, the mutant molecules of haemoglobin (HbS) stack to form monomolecular filaments. Six strands assemble into a heli-coidal microtubule showing six helices of long pitch (review in 19). These microtubules form a cholesteric packing (6). 

Subsequently, Brendstrup [9,25] correlated the TS Cu increase in febrile patients and return to normal in remission, with other parameters associated with disease activity. As shown in Table 5.2, active disease was associated with an increased TS Cu which was directly related to decreased mobility and haemoglobin (Hb) values as well as increased ESR and duration. The mean value of TS Cu in patients with normal mobility differed relatively little from the mean value found for patients with inactive joint lesions. Patients with active RA who showed clinical improvement had a pronounced fall toward normal TS Cu and ESR but these parameters remained relatively unchanged in patients showing no improvement. 

Table 5.2. MEAN MOBILITY INDICES (MI), ERYTHROCYTE SEDIMENTATION RATE (ESR), DURATION, HAEMOGLOBIN(Hb), TOTAL COPPER(C u) AND ACTIVITY OF DISEASE FOR PATIENTS WITH CHRONIC RHEUMATOID ARTHRITIS (25]...

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