Ion binding: patterns of 'affinity' depending on types of acid groups.
Bungenberg de Jong's sequences of cation binding to polymer-bound anionic sites established, over 40 years ago, that the most common cations, Na+, K+, Mg+(+) and Ca+(+), in biological materials behaved differently in the presence of the three most common polyanionic charges, carboxylate, diester phosphate and ester sulphate. He proposed a fundamental mechanism involving polarisability and polarising power, respectively, of the anionic electrons and the cation, which accounted for his observations. We generalised his mechanism to provide a relationship between the pK of the anion and the ion binding spectrum. Extracellular polyanions would be predicted to prefer K+ to Na+, in spite of the preponderance of Na+ in the extracellular space. It is suggested that this preference was important during biosynthesis inside the cell, where K+ is predominant.
Scott
J E
JE
Department of Chemical Morphology (Cell and Structural Biology), Manchester University, UK.
D000143:Acids; D004563:Electrochemistry; D007477:Ions; D000071228:Polyelectrolytes; D011108:Polymers
D000143:Acids; D007477:Ions; D000071228:Polyelectrolytes; D011108:Polymers