Oxygen physiological properties

Figure 38-4. Examples of three types of missense mutations resulting in abnormal hemoglobin chains. The amino acid alterations and possible alterations in the respective codons are indicated. The hemoglobin Hikari p-chain mutation has apparently normal physiologic properties but is electrophoretically altered. Hemoglobin S has a p-chain mutation and partial function hemoglobin S binds oxygen but precipitates when deoxygenated. Hemoglobin M Boston, an a-chain mutation, permits the oxidation of the heme ferrous iron to the ferric state and so will not bind oxygen at all.

Recently, efforts have been initiated to examine intrinsic host-guest chemistry in the solvent-free environment of a mass spectrometer. Of present interest are preliminary reports on perfluorinated hosts, crown ethers and cryptands, which are physiologically compatible and may possess important biological properties, such as the ability to carry oxygen and transport ions through membranes. Specifically, the oxygen-binding properties of... 

Physiological Properties.—A supply of free oxygen is necessary, not only for the continuance of human life, but for that of all organisms... 

The first, important step in the bioconversion of linoleic acid into conjugated linoleic acid (CLA) is the preparation of an adequate amount of bacterial biomass with suitable physiological properties, such as the high activity of key enzymes reliable for the biotransformation. The second step is bioconversion of linoleic acid to CLA. LA conversion to CLA occurs in anaerobic conditions because the presence of oxygen promotes oxidative metabolism in some bacteria and results in lower CLA production (Ogawa et al, 2001). Many bacterial strains of Lactobacillus, Lactococcus, Streptococcus, Bifidobacteria, Propioni-bacterium, Butyrivibrio and bacterial isolated from various sources have been... 

Vaupel P (1992) Physiological properties of malignant tumours. NMR Biomed 5 220-225 Vaupel P (1993) Oxygenation of solid tumors. In Teicher BA (ed) Drug resistance in oncology. Marcel Dekker, New... 

Ascorbic acid is a reasonably strong reducing agent. The biochemical and physiological functions of ascorbic acid most likely derive from its reducing properties—it functions as an electron carrier. Loss of one electron due to interactions with oxygen or metal ions leads to semidehydro-L-ascorbate, a reactive free radical (Figure 18.30) that can be reduced back to L-ascorbic acid by various enzymes in animals and plants. A characteristic reaction of ascorbic acid is its oxidation to dehydro-L-aseorbie add. Ascorbic acid and dehydroascor-bic acid form an effective redox system. 

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