Distribution in living organisms

Ferrihydrite is the iron oxide with the most widespread distribution in living organisms. In the form of ferritin, an iron storage protein, it is found in all organisms from bacteria through to man (in heart, spleen and liver). It occurs in plants as phytoferritin (review by Seckback, 1982). Ferritin plays a key role in iron metabolism it maintains... 

Cytochrome P-450-dependent monooxygenases are widely distributed in living organisms (e.g., mammals, insects, fish, yeasts, plants). In humans, they exist in several organs and tissues with a maximum level in the liver. These monooxygenases are multienzymatic systems that are able to transfer electrons from NADPH or NADH to their terminal component, cytochrome P-450, which contains the site of activation of dioxygen and substrates. They catalyze the insertion of only one oxygen atom of 02 into the substrate (Eq. 7). 

Because of their wide distribution in living organisms and their important roles in biochemistry, pharmacology, and toxicology, cytochromes P-450 have been extensively studied in the last 30 years. More than 500 cytochromes P-450 from various species have already been cloned and sequenced [23]. 

Cytochrome P-450 dependent monooxygenases find wide distribution in living organisms and catalyse the transfer of an oxygen atom from dioxygen to a substrate (reaction IV). 

Cyanocobalamin is widely distributed in living organisms it is found in bacteria, in algae and in animal tissues, but it does not appear to be present in the green leaves of plants. For man, it is an important vitamin, being one of the extrinsic factors of haemopoiesis. It was crystallized in 1948 the crystals are dark red, melt at 320 and their solution has well pronounced absorption bands at 278, 361 and 550 m/i. It contains cobalt and phosphorous and the molecular weight is around 1,500. On acid hydrolysis, cyanocobalamin yields 5,6-dimethylbenzimidazole, ribofuranose, phosphoric add, l-amino-2-propanol and a cobalt complex in which the metal... 

Lipoic acid, or 6,8-dithiolane octanoic acid, is widely distributed in living organisms, intervening in hydrogen transport and acyl radicals by acting as a necesssary coenzyme in the oxidative decarboxylation of pyruvate. If one considers the electrochemical oxidation of the lipoic acid at the surface of the carbon paste electrode (EPC), in contrast to cystine, the molecule is electroactive at potentials less positive than +1.0 V vs SCE. The voltammetric recordings show a perfectly defined oxidation peak which indicates a fast kinetic reaction Ep - Ep/2 = 50 mV. 

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