Cobalt biomolecules

The role of the transition elements in living systems is equally important. Iron is present in biomolecules such as hemoglobin, which transports oxygen from our lungs to other parts of the body. Cobalt is an essential component of vitamin B12. Nickel, copper, and zinc are vital constituents of many enzymes, the large protein molecules that catalyze biochemical reactions. 

In addition to being important in industry, transition metal ions play a vital role in living organisms. For example, complexes of iron provide for the transport and storage of oxygen, molybdenum and iron compounds are catalysts in nitrogen fixation, zinc is found in more than 150 biomolecules in humans, copper and iron play a crucial role in the respiratory cycle, and cobalt is found in essential biomolecules such as vitamin Bi2-... 

Due to high biocompability and large surface are of cobalt oxide nanoparticles it can be used for immobilization of other biomolecules. Flavin adenine FAD is a flavoprotein coenzyme that plays an important biological role in many oxidoreductase processes and biochemical reactions. The immobilized FAD onto different electrode surfaces provides a basis for fabrication of sensors, biosensors, enzymatic reactors and biomedical devices. The electrocatalytic oxidation of NADH on the surface of graphite electrode modified with immobilization of FAD was investigated [276], Recently we used cyclic voltammetry as simple technique for cobalt-oxide nanoparticles formation and immobilization flavin adenine dinucleotide (FAD) [277], Repeated cyclic voltammograms of GC/ CoOx nanoparticles modified electrode in buffer solution containing FAD is shown in Fig.37A. 

A biomolecule aided solvothermal synthesis procedure was used to obtain cobalt sulfide hollow spheres.In a typical method L-cysteine, anhydrous cobalt chloride and different surfactants were dissolved in ethylenediamine. Cysteine was incorporated as a sulfur souree and also to facilitate the microsphere formation. The reaetion mixture was autoclaved at 180 °C for different times after stirring for 15 minutes. The resulting products were washed with deionised water and ethanol several times and placed in a vacuum oven at 60 °C for 4 hours. The hollow... 

In another report using the CDC approach, functional modulation was achieved by controlling LbL film but without a specific biomolecule. In order to achieve this goal, Luz and co-workers [8] assembled two LbL platforms that take advantage of alternate immobilization of cobalt (II) tetrasulfonated phthalocyanine (Co TsPc), chitosan (Chit) and SWCNTs. Co TsPc belongs to a group of metallic phthalo-cyanines that show delocalized 7t-electrons and planar geometry with unique... 

Bao, S. J. et al. 2008. Biomolecule-assisted synthesis of cobalt sulfide nanowires for application in supercapacitors. Journal of Power Sources, 180, 676-681. 

Vitamin B12 is the only known biomolecule that possesses a carbon-metal bond. In the stable commercial form of the vitamin, a cyano group is bonded to the cobalt, and the cobalt is in the +3 oxidation state. The core of the vitamin B12 molecule is a corrin ring [Fig. G.2(b)] with various attached side groups. The corrin ring consists of four pyrrole... 

DNA/protein ratio. Furthermore, less abundant biomolecules such as carotenoids or haem enzymes or non-fluorescent drugs (e.g. cobalt octacarboxyph-thalocyanine) can be detected by taking advantage of the RR effect. These studies are particularly promising for elucidating metabolic processes in cells. 

Figure 7.1.3. Structure of 5 -deoxyadenosine if 5 -deoxyadenosine = R in Figure 7.1.1, the complex is called vitamin B12 coenzyme. The carbon atom of the CH2 group is directly coordinated to the cobalt atom, the only known example of the carbon-metal bond in a biomolecule.

---