The pH in the reversed micellar system of di(ethyIhexyl) sodium sulfosuccinate (Aerosol OT, AOT) / phosphate buffer solutions/octane was determined by a P-NMR technique, and pHs in the reversed micelles containing buffer solutions other than the phosphate buffer solution were measured by the spectrophotometric method with the aid of Phenol Red. pHs in reversed micelIes were found to be substantially determined by the buffer capacity of buffer solutions solubilized into the systems. By means of both the methods, pKa of Phenol Red in the systems was found to be 7.7, which is almost consistent with that in water. Analysis of Na-NMR spectra indicates that the mobility of the sodium ion of AOT is independent of the molar ratio of water to AOT when the ratio is above 7 and is restricted strongly by the interaction with the sulfonate group of AOT. The relationship between pH and the mobility of the sodium ion was discussed on the basis of the data of Na-NMR spectra.T 463 48"

Absorption spectra and induced CD have been measured on aqueous solutions of watersoluble porphyrins with a-helical poly (L-glutamic acid) or a-helical poly (L-lysine) a t different mixing ratios. For the former, porphyrin is porphine-meso-tetra (4-N-methylpyridinium) (TMpyP) , and for the latter, it is porphine-meso-tetra( 4-benzenesulfonate) (TPPS) or porphine-meso-tetra( 4-benzoate) ( T P P C ) . All the solutions of porphyrinpolypeptide systems show hypochromism in the Soret band and induced CD in the Soret region. The CD is characterized by a positive band at a shorter wavelength and a stronger negative band at a longer wavelength. The hypochromicity and the magnitude of molar ellipticities are much larger for the TPPSand TPPC-poly (L-lysine) systems than for the TMpyP-poly (L-glutamic acid) system. Porphyrin ions bind to the a-helix electrostatically, and the two components of the Soret transition of porphyrin are subject to dissymmetric perturbation. TMpyP ions bind to the a-helix at isolated sites, while TPPS ions and TPPC ions are in pairs on the a-helix, that is, two ions bind consecutively and dissymmetrically.In the TMpyP-poly (L-glutamic acid) system a single CD band is associated with each of the two components of the Soret transition, and these are of opposite sign. In the TPPSand TPPC-poly( L-lysine) systems, a pair of positive and negative CD bands is associated with each of the two components, thus giving apparently a single pair of CD bands with a shoulder, owing to partial overlapping.

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