what are chelators?

Question

SOMETHING RELATED TO BIOLOGY

Answer 1

Chelators are small molecules that bind very tightly to metal ions. Some chelators are simple molecules that are easily manufactured (e.g., ethylene diamine tetra acetic acid; EDTA). Others are complex proteins made by living organisms (e.g., transferrin). The key property shared by all chelators is that the metal ion bound to the chelator is chemically inert. Consequently, one of the important roles of chelators is to detoxify metal ions and prevent poisoning. For instance, EDTA is used to treat patients with extreme, life-threatening hypercalcemia. The iron chelator, desferrioxamine, is used to remove excess iron that accumulates with chronic blood transfusions.

Many chelators are used in chemistry and industry. Only a few are clinically useful since most have dangerous side-effects. One important property required of clinically useful chelators is specificity. Since these drugs disperse diffusely in the body, they must bind the target metal ion preferentially over others. Desferrioxamine (Desferal®), for instance, can be used to treat iron overload since the drug binds iron with a large preference over other metal ions such as calcium (Kd=10-31 M for iron, Kd=10-9 M for calcium) (1).

Iron Chelators
Iron chelators can be classified using a number of criteria such as their origin (synthetic versus biologically produced molecules), their interaction with solvents such as water (hydrophobic versus hydrophilic) or their stoichiometric interaction (bidentate versus hexadentate.) Some of these properties have an important impact on the clinical utility of a chelator, as discussed later.

One key clinical feature of iron chelators is the degree to which they are absorbed from the gastrointestinal tract. A clinically highly effective iron chelator such as desferrioxamine has the drawback of very poor absorption from the gastrointestinal tract (2). Consequently the drug must be given parenterally, as a continuous subcutaneous infusion, or as a continuous intravenous infusion (3, 4). The expensive medical paraphernalia required for desferrioxamine administration makes the treatment expensive, and curbs its availability in areas of the world where medical resources are limited. Even when the resources exist to support iron chelation with desferrioxamine, the intrusiveness of pumps and other paraphernalia often impedes patient compliance (5). For these reasons, an intensive search for orally active iron chelators is being conducted by a number of medical researchers.

Answer 2

The Greek origin of the word chelate signifies the plier-like claws of a crab. A chelate is a water-soluble complex between a metal ion and a complexing agent. It usually does not dissociate easily in solution, but forms an inert complex. In labile complexes, however, the metal ion can be readily exchanged. Metal complexes of transition elements are well known here, chelation occurs within a much wider range of elements. Chelating agents yielding soluble metal complexes are also called sequestering agents [1]. A chelating agent has at least two functional groups which donate a pair of electrons to the metal, such as = O, -NH2 or -COO¯. Furthermore, these groups must be located so as to allow ring formation with the metal. Chelating agents are widely found in living systems and are of importance in cellular metabolism
related to biology

It has been well recognized that the use of basic reagents of highest purity is a definite prerequisite for successful work in molecular biology. Therefore many authors of laboratory protocols recommend purification of commercially available basic reagents in order to eliminate interfering traces of chemical impurities. Well known examples are the denaturation reagents phenol (1), formamide (2) and DMSO (2). Additional problems may be caused by contamination of the basic chemicals with traces of enzyme impurities such as DNases, RNases, phosphatases and proteases. Hence time consuming pretreatment of the basic reagents is necessary. To meet the increasing demand for such highpurity reagents used in gene technology experiments, Fluka has recently introduced a specific BioChemika Ultra quality grade: BioChemika Ultra for molecular biology. Products of this group are free of both interfering chemical traces and the above-mentioned enzyme impurities.

Answer 3

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RE:
what are chelators?
SOMETHING RELATED TO BIOLOGY

Answer 4

a caliperlike group that functions as two associating units and fasten to a central atom.

usually this is describing a complex in which a metal ion is bound to two or more atoms creating a coordination of ionic bonds.

that answer your question?

Answer 5

Sure, try cranberry juice :) (thats also good for your urinary system too!)