The spectral shift from 420 to 338 nm when pure bacterial D-amino acid transaminase binds D-amino acid substrates is also exhibited in part by high concentrations of L-amino acids (L-alanine and L-glutamate) but not by simple dicarboxylic acids or monoamines. Slow processing of L-alanine to D-alanine was observed both by coupled enzymatic assays using D-amino acid oxidase and by high pressure l...

We have applied the Transition Path Sampling algorithm to the reaction catalyzed by the enzyme Lactate Dehydrogenase. This study demonstrates the ease of scaling Transition Path Sampling for applications on many degree of freedom systems, whose energy surface is a complex terrain of valleys and saddle points. As a Monte Carlo importance sampling method, transition path sampling is capable of su...

The spontaneous oxidation of an amine group to an imine has been observed experimentally in an octa-aza macrocyclic dinucleating ligand LH(4) coordinated to Cu(II). The reaction is bimolecular and spontaneous in which amine groups of one macrocycle are oxidised and the Cu(II) centres of a second macrocyclic complex are reduced. No additional oxidating or external base agents are required. DFT c...

This review considers the interaction of Complex I with different redox acceptors, mainly homologs and analogs of the physiological acceptor, hydrophobic Coenzyme Q. After examining the physical properties of the different quinones and their efficacy in restoring mitochondrial respiration, a survey ensues of the advantages and drawbacks of the quinones commonly used in Complex I activity determ...

ATP synthases utilize a proton motive force to synthesize ATP. In reverse, these membrane-embedded enzymes can also hydrolyze ATP to pump protons over the membrane. To prevent wasteful of ATP hydrolysis, distinct control mechanisms exist for ATP synthases in bacteria, archaea, chloroplasts and mitochondria. Single-molecule Förster resonance energy transfer demonstrated that the C-terminus of ro...

Point defects such as oxygen vacancies and protonic interstitials are not only essential for ionic conductivity in oxides since they also affect the mechanical electromechanical properties. These properties of nominally dry hydrated proton-conducting BaZr0.85M0.15O2.925+?H2? (M = Al, Ga, Sc, In, Y, Eu) ceramics investigated. Doping decreases Young's modulus with increasing radii difference betw...

Some CLC proteins function as passive Cl(-) ion channels whereas others are secondary active chloride/proton antiporters. Voltage-dependent gating of the model Torpedo channel ClC-0 is modulated by intracellular and extracellular pH, possibly reflecting a mechanistic relationship with the chloride/proton coupling of CLC antiporters. We used inside-out patch clamp measurements and mutagenesis to...

Fluorescein is a complex fluorophore that can exist in one or more of four different prototropic forms (cation, neutral, dianion, and monoanion) depending on pH. In the pH range 6-10, only the dianion and monanion forms are important. In a previous article, we showed by steady-state fluorescein measurements that an excited fluorescein molecule displays excited-state proton transfer reactions wh...