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Yeast amino acid transporters of the APC superfamily are responsible for the proton motive force‐driven uptake of amino acids into the cell, which for most secondary transporters is a reversible process. The l‐lysine proton symporter Lyp1 of Saccharomyces cerevisiae is special in that the Michaelis constant from out‐to‐in transport ( Kmout→in ) is much lower than Kmin→out , which allows accumulation of l‐lysine to submolar concentration. It has been proposed that high intracellular lysine is part of the antioxidant mechanism of the cell. The molecular basis for the unique kinetic properties of Lyp1 is unknown. We compared the sequence of Lyp1 with APC para‐ and orthologues and find structural features that set Lyp1 apart, including differences in extracellular loop regions. We screened the extracellular loops by alanine mutagenesis and determined Lyp1 localization and activity and find positions that affect either the localization or activity of Lyp1. Half of the affected mutants are located in the extension of extracellular loop 3 or in a predicted α‐helix in extracellular loop 4. Our data indicate that extracellular loops not only connect the transmembrane helices but also serve functionally important roles., We performed alanine‐scanning mutagenesis of the extracellular loops of the yeast lysine transporter Lyp1. We find positions that affect either the localization or activity of Lyp1. Half of the affected mutants are located in the extension of extracellular loop 3 or in a predicted α‐helix in extracellular loop 4. We conclude that extracellular loops of amino acid transporters of the APC superfamily serve functionally important roles.

We present a combined electrochemical, kinetic, and synthetic study with a novel and easily accessible class of titanocene catalysts for catalysis in single-electron steps. The tailoring of the electronic properties of our Cp2 TiX-catalysts that are prepared in situ from readily available Cp2 TiX2 is achieved by varying the anionic ligand X. Of the complexes investigated, Cp2 TiOMs proved to be either equal or substantially superior to the best catalysts developed earlier. The kinetic and thermodynamic properties pertinent to catalysis have been determined. They allow a mechanistic understanding of the subtle interplay of properties required for an efficient oxidative addition and reduction. Therefore, our study highlights that efficient catalysts do not require the elaborate covalent modification of the cyclopentadienyl ligands.

Herein, the conversion times of biomass pyrolysis are measured at temperatures between 450 and 550 °C and particle size fractions between 0 and 400 μm using a cyclonic thermogravimetric analyzer (TGA) device. Beech, spruce, and ash wood are investigated, as well as torrefied samples. The conversion time decreases with the increasing temperature from 7 to less than 1 s. The influence of the type of biomass on the conversion time is limited and only significant for low temperatures, when kinetics dominates the conversion process. A clear influence of the torrefaction process on the pyrolysis conversion time is noted and can be explained by the modified porosity of the biomass particles during the torrefaction process. Kinetic data are extracted from the conversion times, and a model is developed for a better interpretation of the measured results. The model shows good comparison with the experimental data and may also be used for design purposes of fast pyrolysis reactors.