Alanine, configuration molecular model

Hidaka et al. [77] reported that amphoteric Af-(2-hydroxyethyl)- -(2-hydroxyalkyl)-P-alanines s cmc values greatly depend on the nature of the electrolytes added to its nearly neutral aqueous solution, and that the cmc value decreased in the following order NaCl > CaClj > Na2S04. Also, their calcium stability is superior to that of A-dodecyl-P-alanines. The effect of pH on this amphoteric amino acid surfactant was smdied in the presence of 0.1 M NaCl [78] and the results showed that the cmc value increased on the acidic side below the isoelectric point pi = 6.8 and remained almost unchanged on the alkaline side. Examination of the configuration with molecular models indicates that the cationic ionization of the amino group on the acidic side probably takes place within the micelle, whereas under alkaline circumstances the anionic ionization of the carbonyl group occurs on the micellar surface. This makes the electrostatic potential for ionization different on the acidic and alkaline sides. 

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