Carbohydrates biological oxidation

Carbohydrates. — Biological Oxidation. — Fats. — Terpenoids. — Phenols. 

Krebs, H.A. (1943). The intermediary stages in the biological oxidation of carbohydrate. Advances in Enzymol. 3, 191-252. 

Widespread Mabis (apple), Rosa (rose hip) (Rosaceae), Citrus (Rutaceae), Capsicum (Szegedi paprika) (Solanaceae) spp. Vitamin C reaches 20-300 mM in chloroplasts discovered by Albert Szent-Gyorgyi (Hungary/ USA, Nobel Prize, 1937 [vitamin C biological oxidations]) structure synthesis (Sir Walter Haworth (UK, Nobel Prize, Chemistry, 1937, [carbohydrates vitamin C]) identified by W.A. Waugh C.G. King (USA)... 

Next, let us take a look at the overall picture of the biological oxidation of carbohydrates. We start with glycogen ( sugar-former ) the form in which carbohydrates are stored in the animal body. This, we have seen (Sec. 35.9), is a starch-like polymer of D-glucose,... 

The overproduction of RONS may damage biological systems through peroxidation of membrane hpids, oxidative damage of nucleic acids and carbohydrates, and oxidation of... 

The processes of life also depend on oxidation of organic substrates, whereby metabolic energy is derived from the overall oxidation of carbohydrates, fats, and proteins to carbon dioxide and water, among other products, as illustrated in Equation 16.5. Potentially poisonous substances are commonly detoxified by biological oxidation to more benign substances. Thus, nicotine, which is toxic to humans if present in sufficiently high concentration, is oxidized in the liver to cotinine (Eq. 16.6), a substance of low toxicity. 

Riboflavin in its coenzyme forms (FMN and FAD) plays key metabolic roles in biological oxidation-reduction reactions involving carbohydrates, amino acids and lipids, and in energy production via the respiratory chain. These coenzymes also act in cellular metabolism of other water-soluble vitamins through the production and activation of folate and pyridoxine (vitamin Bg) to their respective coenzyme forms and in the synthesis of niacin (vitamin B3) from tryptophan. In addition, some neurotransmitters and other amines require FAD for their metabolism. Recently, Chocano-Bedoya et al. (2011) suggested a possible benefit of high intakes of riboflavin (about 2.5 mg/ day) from food sources on the reduction of incidence of premenstrual syndrome. 

Gershanovich VN (1965) Investigation of synthesis, regulation and enzyme activity of carbohydrate metabohsm and biological oxidation in different cell systems. DSc thesis, Moscow State University, Moscow... 

Carbon occurs in the biosphere either reduced (methane, fatty acid, carbohydrate) or oxidized (alcohol, aldehyde, carbonic acid, carbon dioxide). The valence state 0 is found only in coal (a compound of biological origin). 

Riboflavin, also called vitamin B2, is stmcturally composed of an isoafloxazine ring with a ribityl side chain at the nitrogen at position 10. This vitamin functions metabol-icafly as the essoitial component of two flavin coenzymes, flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN), complexed with proteins, which act as intmnediaries in transfers of electrons in biological oxidation-reduction reactions. Both FAD and FMN function as coenzymes for flavoproteins of flavoenzymes. Flavoproteins are essoitial for the metabolism of carbohydrates, amino acids, and lipids and for pyridoxine and folate conversion to their respective coenzyme forms. 

Biological oxidation proceeds in four stages if we introduce a carbohydrate, such as the ubiquitous glucose, into the process (Fig. 51) ... 

The end products of catabolism are mainly CO2 and H2O. Carbon dioxide arises largely from decarboxylation in the citric acid cycle water originates from biologic oxidation in the respiratory chain. Since the breakdown products of the three main foodstuffs, carbohydrates, fats, and proteins, all enter these common terminal pathways, it is not surprising that these foodstuffs can replace each other as nutrients. 

Other Processes. Isopropyl alcohol can be prepared by the Hquid-phase oxidation of propane (118). It is produced iacidentaHy by the reductive condensation of acetone, and is pardy recovered from fermentation (119). Large-scale commercial biological production of isopropyl alcohol from carbohydrate raw materials has also been studied (120—123). 

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