ATP synthase (F₀F₁) is a major energy supplying enzyme of cells utilizing the proton motive force across the biomembrane. It consists of a catalytic portion called F₁ and a proton channel portion called F₀. For elucidation of the chemical reaction of F₀F₁, thermophilic F₀F₁ (TF₀F₁) was used, because it is stable and could be reconstituted without Mg-ATP. A new method for incorporating F₀F₁ in a planar lipid bilayer was developed by using a lipid monolayer technique and liposome fusion. Then the electrogenic proton translocation of F₀F₁ was directly measured. In contrast to the previous hypotheses on the ATP synthesis, direct measurement of II+ current through TF₀F₁ incorporated into a planar lipid bilayer, 3H+/ATP stoichiometry was obtained. The primary structure of TF₀F₁ was established by sequencing its operon DNA and subunit peptides. The stereochemistry of the reaction using [¹⁶O, ¹⁷O, ¹⁸O, ³⁵O] thiophosphate supported the a pathway for associative nucleophilic displacement on a phosphoric ester. The site directed mutagenesis of the residues of F₁ homologous to Mg-ATP binding site of adenylate kinase revealed their essential role in the reaction.

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Fourier transform infrared (FTIR) -attenuated total reflection (ATR) spectra have been studied of Langmuir-Blodgett (LB) films of stearic acid with 1 to 9 monolayers. Difference in the spectral features observed among respective monolayers suggests that there are changes in structure, subcell packing, and molecular orientation as a function of the number of monolayers. (1) The hydrocarbon chains of stearic acid in the first monolayer are in the hexagonal subcell packing where each chain is freely rotated around its long axis oriented perpendicular to the surface. However, the molecules in the upper monolayers crystallize with the monoclinic form where the hydrocarbon chains are packed alternately and are inclined at the angle about 30° with the surface normal. (2) Stearic acid occurs as the cis configuration for the C=O and C_α-C_β bonds in the 1- and 2-monolayer films, but the trans configuration starts to appear in the 3-monolayer film.
Band intensity enhancement of FTIR-ATR spectra of the stearic acid LB film is obtained by evaporation of thin Ag island layers. It is found that in the 1-monolayer LB film, all stearic acids react with evaporated Ag forming silver stearate and the symmetric COO^- stretching band is enhanced a factor of 30. This phenomenon is ascribed to the electric field enhancement due to collective electron resonances associated with the island nature of the thin Ag layers.

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Bilayer membranes are formed from single-chain, double-chain, and triple-chain compounds with different kinds of hydrophilic head groups. Rigid aromatic segments are usually requirea for the single-chain amphiphiles. A modular concept is useful for a systematic understanding of the structures of these compounds.
Dynamic and static morphologies of the bilayer aggregates are determined by the membrane physical state and the component structure. For example, chiral bilayers can produce helical superstructures, and morphologies of bilayers of some single-chain amphiphiles are interpretable in terms of the geometry of the rigid segment. As for the molecular organization, the relation of the chemical structure and the component orientation is elucidated in the case of azobenzene bilayers. The photophysical and photochemical properties change accordingly. Controlled orientations of metal chelates in bilayer are ascertained by esr spectroscopy. The component distribution can be modified by appropriate combinations of the bilayer constituent.
Regular, multi-bilayer films are prepared by casting of aqueous bilayer dispersions. Stable monolayers are readily formed at the air-water interface from bilayer-forming compounds and they can be transfered onto solid substrates as the Langmuir-Blodgett film. These films may be used as permselective membranes.

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Chemical conversion of light energy by the aid of membrane system is described. Light-in-duded electron transfer is the most important process there. In this process, the prevention of backward electron transfer, in other words, the charge separation is the key point.
The introduction of the heterogeneous system such as membrane can bring about the effective charge separation.
Several examples of the application of LB film, vesicle and liposome to improve the conversion efficiency are shown.

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A model is described for the potential distribution across a charged membrane surface. This model assumes that membrane-fixed charges are distributed through a surface layer of non-zero thickness d and that electrolyte ions can penetrate the surface layer. Along the lines of this model, we discuss various interfacial electric phenomena-potential distribution across a membrane, electrophoresis, and electrostatic interaction of membranes-in comparsion with results predicted from the conventional model assuming d=0. The Donnan potential is shown to play a fundamental role in the electric behavior of membranes.

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Measurements of bi-ionic potential were carried out across anion-exchange membranes for KCl/KIO₃ system and across cation-exchange membranes for KCl/NaCl system. The transport numbers of counterions in the membranes were nearly unity under the experimental conditions. The increase of bi-ionic potential was observed with an increase in the external electrolyte concentration. The electrolyte concentration dependence of bi-ionic potential would be due to both the changes in the mobility ratio of two counterions in the membrane and in the difference of standard chemical potentials between the membrane and the external solution.

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A theory is developed for coupled transport processes in continuous systems. A thermodynamic flux at a position can be driven by forces at different positions, which is a kind of cross phenomena. This nonlocal phenomenological relation between thermodynamic forces and fluxes removes unsatisfactory features in the customary theory. The equation of fluid motion, for example the Navier-Stokes equation, has been assumed to derive the phenomenological relations, in the customary theory. However, in the present theory, it is a consequence of the theory, and is simply an example of the nonlocal phenomenological relations. This equation of motion shows a coupling between the flow velocity of vectorial property and pressure Sensor due to viscosity. Similarly, on the basis of the nonlocal coupling theory developed here, it is shown that the diffusion may be coupled with the chemical reaction even in isotropic systems such as electrolyte solutions. This kind of coupling is closely related to the active transport in living organisms.

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Thermal membrane potential was measured using various ion-exchange membranes. The results follow a theory previously proposed. Thermal membrane potential was large when the membrane has high molality of fixed charges. Characteristic properties in thermal membrane potential were not observed for perfluorinated membranes compared with that for charged membranes of hydrocarbon polymer matrix. A slight deviation from the theory was observed in the dependence of temperature coefficients of thermal membrane potential on the molality of external solution. This deviation would be due to some change in the state of hydrated ions and water in membranes with the change of swelling pressure.

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Poly (L-lactide) microcapsules were observed to be hydrolytically degraded rapidly in a strongly alkaline solution into lactic acid as the final product. The degradation was accelerated when poly (L-lactide) microcapsules were immersed in solutions of high ionic strengths. The effects of pH and ionic strength of the bulk solution were interpreted in terms of the electric potential distribution in the membrane.
The charge distribution in the microcapsule membrane changes during degradation. In the intact poly (L-lactide) microcapsule membrane, the charged groups are considered to be distributed uniformly in it. In the early stage of the degradation process, the zeta potential became more negative with the time elapsed. Analysis of the ionic strength dependence of the zeta potential on the basis of a simple model shows that hydrolytic scission of ester bonds of the polymer chains takes place preferentially at the microcapsule membrane surface to create negative charges localized at the membrane/solution interface. In the later stages of the degradation process, the zeta potential again became less negative. This suggests that liberation of degraded segments takes place in the later stages. It was concluded, therefore, that both the cleavage of the ester bonds and the liberation of degraded segments of poly (L-lactide) molecules start from the surface of poly (L-lactide) microcapsules.

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Self-diffusion coefficients were determined for organic adsorbates (2-propanol and acetone) in triamine-modified and unmodified controlled-pore glasses, using the pulsed field gradient NMR technique. Saturated amounts of adsorption were decreased considerably by the surface modification, indicating the reduction of free space for adsorption. With modified surface, both diffusivity and permeability were increased irrespective of the state of adsorption (unmixed or mixed). With unmodified surface, the order of diffusivity was reversed for 2-propanol and acetone by changing the state of adsorption ; the same reversal was also observed for permeability. This common characteristic feature is interpreted in terms of preferential adsorption of acetone (vs. 2-propanol) on hydroxyl (acidic) adsorption sites on the glass surface. Modification of surface acidity by treating with aqueous aluminium nitrate (or sodium acetate) supports this view.
Together with the common trend in diffusivity and permeability for the triamine-modified surface, importance of diffusivity in determining the permeation property is suggested.

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Saturation transfer electron paramagnetic resonance spectra (ST-EPR) was successfully applied to spin labeled oriented multibilayers to explore the anisotropic fluctuation of lipid membranes in the slow motional domain. The integrated value of ST-EPR spectra provides information about the correlation time of motion in multibilayers. A highly anisotropic dynamic structure with widely different correlation times was found in the gel phase of the phospholipid multibilayers containing cholesterol.

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