Iodized species

The number of the iodine atoms incorporated per protein heavily influences its binding ability. The greater the ratio of molecules of iodine atoms to molecules of protein in the reaction mixture the more iodine is incorporated into the protein, and the less immune reactivity and biological activity of the iodized protein. The stoichiometric relation of the reactants in the iodination mixture is an important factor too much iodine and the protein is dead. It is advisable to perform the reaction first with Todine (nonradioactive) and to check the iodized species, especially the simply iodized compoimd, for biological effects. 

Cobalt is a component of the vitamin B12 molecule but a deficiency of cobalt has not been demonstrated in poultry fed a diet adequate in vitamin B12. Therefore, supplementation with this element is not normally necessary. Diets containing no ingredients of animal origin (which contain vitamin B12) contain no vitamin B12. Therefore, poultry fed on all-plant diets may require dietary cobalt, unless the diet is supplemented with vitamin B12. In practice, many feed manufacturers use a cobalt-iodized salt for all species since cobalt is needed in ruminant diets. This avoids the need to stock separate salt types for ruminant and non-ruminant diets and the inclusion of cobalt provides some insurance in case the poultry diet is lacking sufficient vitamin B12. 

The observation of toxicity of iodine mainly focused on the iodide or iodate, which is normally present in iodized salt, milk, water and leachate of foodstuffs. However, the toxicity of some other species of iodine may be much higher than that of iodide and iodate. For the prevention of iodine deficiency disorders, iodized oil was used as an injection or administered orally in many countries iodized oil is normally produced by binding iodine atoms to the polyunsaturated fatty acid in the oil (Zimmermann et al, 2000). After administration, it was supposed that iodine is released gradually as iodide to maintain a constant supply of iodine to the body. Experience in the past decades shows that the utilization of iodized oil is safe. However, acute poisoning of iodized oil to children who are orally administered was reported in China in 1998 this may be related to the species of iodine, which may be more toxic than iodide or iodate. Iodine has been used as an effective, simple, and cost-efficient means of water disinfection (Backer and Hollowell, 2000), in which the active disinfectant species are elemental iodine and hypo-iodous acid. Doses of iodine below 1 mg/1 kill bacteria within minutes. Elemental iodine and hypoiodous acid remain in the disinfected water, which may be toxic to humans. 

If the monoiodized molecule species cannot be isolated, you have a mixture of iodized and uniodized molecules (i.e., you have to determine the specific radioactivity). This is calculated as the amoimt of incorporated radioactivity divided by the amoimt of molecules (iodized + uniodized) in mol. The specific activity is given in Ci/mM. On the basis of the specific activity, you can calculate how many atoms of the radioactive isotope are contained in a molecule (Figure 2.2). Thus, if you have a protein derivatized with iodine and with a specific radioactivity of 2,200 Ci/mM, each protein molecule contains one iodine atom on average. 

The bane of indirect iodination methods is the low specific activity of the product. For a good yield of the conjugation reaction, you need to add large amounts of the molecule to be derivatized. However, if the specific activity is too low, you have to separate iodized from uniodized species, which can be tricky (recommendation make the iodine product with Bolton Hunter and a trace of Bolton Hunter and use it to calibrate the separation method beforehand). Bolton Hunter reagent, for example, is expensive and unstable in watery solution, and the incorporation of the large lipophile group can have even more disastrous effects on the activity of a compound than the conversion of a phenyl residue into a l-phenyl residue. 

Kan Z (1996) Dynamic study of iodized oil in the liver and blood supply to hepatic tumors An experimental investigation in several animal species. Acta Radiol SuppI 408 1-25 Kan Z, Wallace S (1997) Transcatheter liver lobar ablation an experimental trial in an animal model. Eur Radiol 7 1071-1075... 

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