Amino acid chemoreception: Effects of ph on receptors and stimuli.

A current model of amino acid chemoreception has generated the idea that pH affects the efficiency of stimulus-receptor binding by altering the charge distribution on stimulus molecules. The model suggests that amino acids are maximally stimulatory near their isoelectric points. We point out that, within a broad range of pH values, changes in stimulant amino acids cannot account for altered chemoresponsiveness. We suggest instead that pH-induced changes in chemoreception are a result of changes in charge distribution on the protein receptor.