BAPTA
Encyclopedia
BAPTA is a calcium
-specific polyamino carboxylic acid
. The presence of four carboxylic acid
functional group
s makes possible the binding of two magnesium ions. The extensive flexibility of the carboxylate ligands is critical to the coordination of magnesium, or other metal ions. Recent studies have demonstrated that the BAPTA moiety actually binds to zinc ions with a substantially higher affinity than calcium. Interestingly, it appears that the assumption of the chelator's calcium preference may have contributed to evidence for the role of calcium ions as causal agents in ischemia (stroke), and brain trauma. Based on this evidence, pharmacological agents en masse have been designed and synthesized, yet have met with little success.
There are a range of reported values for the dissociation constant of BAPTA, though 0.2 µM appears consistently. The rate constant for calcium binding is 500 µM−1 s−1.
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
-specific polyamino carboxylic acid
Polyamino carboxylic acid
thumb|left|120px|a metal complex with the [[EDTA]] anionthumb|120px|the [[glycine|glycinate]] ion can form a chelate complex with a metal ionthumb|120px| β [[alanine]]...
. The presence of four carboxylic acid
Carboxylic acid
Carboxylic acids are organic acids characterized by the presence of at least one carboxyl group. The general formula of a carboxylic acid is R-COOH, where R is some monovalent functional group...
functional group
Functional group
In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of...
s makes possible the binding of two magnesium ions. The extensive flexibility of the carboxylate ligands is critical to the coordination of magnesium, or other metal ions. Recent studies have demonstrated that the BAPTA moiety actually binds to zinc ions with a substantially higher affinity than calcium. Interestingly, it appears that the assumption of the chelator's calcium preference may have contributed to evidence for the role of calcium ions as causal agents in ischemia (stroke), and brain trauma. Based on this evidence, pharmacological agents en masse have been designed and synthesized, yet have met with little success.
There are a range of reported values for the dissociation constant of BAPTA, though 0.2 µM appears consistently. The rate constant for calcium binding is 500 µM−1 s−1.