Molecular aggregates or molecular automata that could appear during chemical and protobiological evolution have boundary conditions of their own. The preceding products during molecular synthesis keep providing the boundary conditions for the subsequent production process. The successive feedback from product to production and the resulting internalization of the boundary conditions are the main mechanism underlying the evolution of functional molecular aggregates. The internalization of the boundary conditions and their endogenous changes with time are identified in the experimental protobiogenesis of thermal polymerization of amino acids, microsphere formation from the resulting thermal proteins and the reproduction of these microspheres. The physical process responsible for the internalization of the boundary conditions is material flow equilibration of an open material aggregate. Material flow equilibration is a process by which an open material aggregate constantly and endogenously changes its interaction with its exterior so as to maintain the continuity of material flow there. Both variations and constraints applied to the evolution of material aggregates are due to material flow equilibration and thus are inseparable. Protobiological information originates in the physical process by which the boundary conditions for molecular aggregates are formed endogenously.
Fluxes of ions such as H+, Cl-, K+, Na+, and HCO3- in the parietal cell are summarized. Gastric vesicles containing membrane (H++K+)-ATPase are isolated from the parietal cell and can accumulate H+ in exchange for K+ (H+/K+ antiport, nonelectrogenic) on the addition of MgATP. The intravesicular pH falls as low as 1-3, dependending on the methods used for estimation. The biochemical properties of the ATPase are summarized. Onset of acid secretion changes the morphology of the parietal cell at the secretory surface. This is explained by the increase in KCl conductance of gastric vesicle membrane. The increase is due to the opening of the anion channel caused by S-S cross-linkings.
Self-sustained oscillation of excitable membranes synchronizes with a periodic stimulation because of its nonlinearity. The oscillation, however, becomes irregular under some value of amplitude and frequency of the stimulation. The present review mainly shows the existence of the chaotic behavior of the Nitella internodal cell and the Onchidium silent neuron. Stroboscopic representation of irregular oscillation forms a strange sttractor. Its hyperbolicity results from the nonlinear characteristics of the membrane, i. e., the threshold and the refractory period. The state points on the attractor are mixed by Baker, s transformation and the map is a convex function. The irregualr response is the chaos which is subject to the deterministic dynamics. The phase diagram of the nonlinear response was obtained in the Nitella cell; there exist the 1/n-harmonic (n is integer), the m/n-harmonic (m and n are integers, m≠1), the quasiperiodic and the chaotic oscillations.
A Resonance Raman label, which is a submolecular probe for interactions in biochemical and biological systems, can provide a detailed vibrational spectrum from a specially designed chromophore when it is bound to a biochemically active site. The resonance Raman label technique was introduced by Carey et al. in 1972. Since then the technique has been applied to systems where time-dependent effects are not observed, such as enzymeinhibitor, antibody-hapten, and drug-receptor interactions. Recently the application of this method has been extended to enzyme-substrate reactions. The first example of enzyme- substrate reactions discussed in this review includes a cinnamoyl group in the active site as a resonance Raman probe. The resonance Raman spectrum of 4-amino-3-nitro cinnamoylpapain was totally distinct from that of the substrate or the product. Comarison of the spectrum of the enzyme-substrate intermediate with the spectra of model compounds revealed that there is a highly polarized π-electron system in the active site binding the acyl group. The second example of enzyme-substrate reactions uses dithio chromophore as a resonance Raman probe. The resonance Raman spectrum of dithioacylpapain enabled us to monitor the vibrational spectrum of the bonds undergoing catalytic transformation in the active site. The study. revealed that the effect of the active site is to select, from a mixture of at least two thermodynamically accessible states, the single conformer in which an intramolecular interaction is occurring within the acyl group.