The quantum efficiency ΦMA of MA production from the photoelectrochemical reduction of OAA followed ΦMA = 0.13 [OAA] (2.1 × 10−3 + [OAA])−1 and was independent of temperature. To evaluate the importance LCZ696 price of this forward rate under a prebiotic scenario, we also studied the temperature-dependent rate of the backward thermal decarboxylation of oxaloacetate to pyruvate (PA), which followed an Arrhenius behavior as log (k −2/s−1) = 11.74–4,956/T. These measured rates were employed in conjunction with the indirectly estimated carboxylation rate of pyruvate to oxaloacetate to assess the possible importance of mineral photoelectrochemistry

in the conversion of oxaloacetate to malate under several scenarios of prebiotic conditions on early Earth. As an example, our analysis shows that there is 90% efficiency and 3-year/cycle forward velocity for the OAA → MA step of the rTCA cycle at 280 K. Efficiency and velocity both decrease for increasing temperature. These results suggest high viability for mineral photoelectrochemistry as an enzyme-free engine

to drive the rTCA cycle through the early eons of early https://www.selleckchem.com/products/sch772984.html Earth, at least for the investigated OAA → MA step. Smith, E. and Morowitz, H. J. (2004). Universality in intermediary metabolism. PNAS, 101:13168–13173. Thauer, R. K. (2007). A Fifth Pathway of Carbon Fixation. Science, 318, 1732–1733. Wachtershauser, G. (1990). Evolution of the first metabolic cycles. PNAS, 87, 200–204. Zhang, X. V. and Martin, S. T. (2006). Driving Parts of Krebs Cycle in Reverse through Mineral Oxalosuccinic acid Photochemistry. J. Am. Chem. Soc., 128, 16032–16033. E-mail: mig@deas.​harvard.​edu Irradiation of Nucleic Acid

Bases Adsorbed in Na-Montmorillonite in the Context of Chemical Evolution Betzabe Zamora, Adriana Melndez, Andres Guzman, Alicia Negrn-Mendoza, Sergio Ramos-Bernal Instituto de Ciencias Nucleares, Universidad Nacional Autnoma de Mexico, UNAM. Cd. Universitaria, A.P. 70–543, 04510 Mexico, D.F. Mexico Nucleic acid bases are part of important compounds in biological systems, such as GDC-0994 solubility dmso genetic and energy utilization processes. Most of the bases are readily formed in prebiotic conditions. Their synthesis and stability in environmental conditions is of paramount importance in chemical evolution (Miller and Orgel, 1974). On the other hand, Clay minerals might have played an important role on the early Earth. They are considered the most likely inorganic material to promote organic reactions at the interface of the hydrosphere and lithosphere (Bernal, 1951). The relevance of clay minerals in the emergency of the origin of life is due to their ancient origin, wide distribution and especially for their physico-chemical properties (Negron-Mendoza and Ramos-Bernal, 2004). There are several routes for the synthesis of nucleic acid bases in simulation experiments of the primitive Earth (Miller and Orgel, 1974).