CO-haemoglobin

Furthermore, 02 binding must occur selectively amongst other atmospheric components such as water, N2, C02 and even excellent ligands for Fe(II) such as CO. Haemoglobin is thus an excellent example of a functional and selective supramolecular receptor. 

Eucolloidal (pol. degree > 500) Natural rubber, synthetic rubbers (neoprene. Buna, Butyl-rubber, Thiokol) Natural cellulose fibres (wood, cotton, flax, hemp) starch pectin. Keratin CO-haemoglobin Serum albumin Haemocyanin ditto, in the highest polymerisation stage Polymerised shellac, damar and copal. Phenol- or urea-formaldehyde between the B-and C-stages... 

Wliat are the structural dynamics of the tetramer as a whole The haemoglobin bound to O2 (Flb02) is not photoactive, so the CO adduct, FlbCO, is used instead. 

Figure Bl.2.11. Biologically active centre in myoglobin or one of the subunits of haemoglobin. The bound CO molecule as well as the proximal and distal histidines are shown m addition to the protohaeme unit. From Rousseau D L and Friedman J M 1988 Biological Applications of Raman Spectroscopy vol 3, ed T G Spiro (New York Wiley). Reprinted by pennission of John Wiley and Sons Inc.

Wlien a strong electron-donor ligand such as pyridine is added to tlie reaction mixture, it can bond so strongly to tlie Rli tliat it essentially drains off all tlie Rli and shuts down tlie cycle it is called a catalyst poison. A poison for many catalysts is CO it works as a physiological poison in essentially the same way as it works as a catalyst poison it bonds to tlie iron sites of haemoglobin in competition witli O. ... 

Figure C3.1.7. Time-resolved optical absorjDtion data for the Soret band of photo lysed haemoglobin-CO showing six first-order (or pseudo-first-order) relaxation phases, I-VI, on a logaritlimic time scale extending from nanoseconds to seconds. Relaxations correspond to geminate and diffusive CO rebinding and to intramolecular relaxations of tertiary and quaternary protein stmcture. (From Goldbeck R A, Paquette S J, Bjorling S C and Kliger D S 1996 Biochemistry 35 8628-39.)...

Carbon monoxide, CO. Carbon monoxide is a colourless, odourless gas. It is extremely poisonous, since the haemoglobin of the blood... 

The above account of selectivity of inorganic plus organic chemistry in synthesis is given rather extensively to stress three points. All the four (Mg, Fe, Co and Ni) porphyrin products came from one source, the synthesis of uroporphyrin. The basis of selection is very different from that in primitive centres which use thermodynamic stability constant selectivity based on different donor atoms for different metal ions. Here, all ion complexes have the same donor atoms, nitrogen, the most constrained being the coordination of Mg2+ by five nitrogens exactly as is seen for Fe in haemoglobin. Hence, there also has to be a new control feedback to ensure that the appropriate quantities of each metal cofactor is produced in a balanced way, that is synthesis from uroporphyrin has to be divided based upon... 

Models for haemoglobin and myoglobin. It has been known for a long time that a range of synthetic Co(n) complexes are able to bind reversibly dioxygen in a manner related to the natural systems (Basolo, Hoffman Ibers, 1975 McLendon Martell, 1976). However, similar complexes of iron do not normally function as 02 carriers - rather oxidation to Fe(m)... 

The multiplier 10 is used because Cao2 is measured inml.dl-1 whereas CO is measured in l.min-1. The 02 content of the blood is calculated using a specific equation that depends mainly on haemoglobin concentration, [Hb] and saturation (Sats). 

CO Neurological symptoms, impairment of reflexes and visual acuity, headache, dizziness, nausea, confusion. Fatal in high concentrations because of irreversible binding to haemoglobin. NA NA... 

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