We report the proton affinities (PAs) and gas-phase basicities (GBs) of pyrogallol (1,2,3-trihydroxybenzene) phloroglucinol (1,3,5-trihydroxybenzene), as determined by high level quantum chemical calculations a series isodesmic transfer reactions. These yet unmeasured values have relevance to release active species from nanocarriers derived calixarene family macrocycles. The PAs GBs obtained fo...

The uncoupling protein (UCP) of brown adipose tissue is a regulated proton carrier which allows uncoupling of mitochondrial respiration from ATP synthesis and, therefore, dissipation of metabolic energy as heat. In this article we demonstrate that, when UCP is expressed in Saccharomyces cerevisiae, it retains all its functional properties: proton and chloride transport, high-affinity binding of...

Proton 1H electron-nuclear double resonance spectra were obtained from cobalt-substituted hemoglobin A. For oxy cobalt-substituted hemoglobin (CoHb), two major couplings were found. One is exchangeable by deuterium and has a coupling of approximately 5.6 MHz which is assigned to the N epsilon 2-proton of the distal histidine (E7), interacting with the ligand. The other splitting (approximately ...

Mechanistic studies show the importance of iodide displacement by additives that accelerate reactions of samarium diiodide. The key feature important for acceleration of reaction rate is the use of proton donors and other additives that have a high enough affinity for Sm(II) to displace iodide yet do not saturate the coordination sphere inhibiting substrate reduction.

A solvent deuterium isotope effect on the catalytic affinity (km) and catalytic constant (kcat) of tyrosinase in its action on different monophenols and o-diphenols was observed. The catalytic constant decreased in all substrates as the molar fraction of deuterated water in the medium increased, while the catalytic affinity only decreased for the o-diphenols with an R group in C-1 [-H, -CH3 and...

Escherichia coli alkaline phosphatase (AP) can hydrolyze a variety of chemically diverse phosphate monoesters while making contacts solely to the transferred phosphoryl group and its incoming and outgoing atoms. Strong interactions between AP and the transferred phosphoryl group are not present in the ground state despite the apparent similarity of the phosphoryl group in the ground and transit...

Cytochrome c oxidase transfers electrons and protons for dioxygen reduction coupled with proton pumping. These electron and proton transfers are tightly coupled with each other for the effective energy transduction by various unknown mechanisms. Here, we report a coupling mechanism by a histidine (His-503) at the entrance of a proton transfer pathway to the dioxygen reduction site (D-pathway) o...

Many yeasts can aerobically catabolize exogenously supplied glycosides that are hydrolysed in the cytosol, but few do so anaerobically. This is so, even for yeasts that use one or more of the component hexoses anaerobically. The phenomenon, called the Kluyver effect, appears to be brought about by a combination of the following four factors: (i) fast transport of the glycosides into the cells i...

The spectroscopic and proton- and Zn(II)-binding properties of two new members of the Zinpyr family of fluorescent sensors are reported. In ZP1B and ZP3B, a (2-picolyl)(4-picolyl)amine (2,4-DPA) moiety is installed in place of the di(2-picolyl)amine (2,2-DPA) ligand used in the parent sensors ZP1 and ZP3. This modification has the benefit of both lowering the proton-induced turn-on at physiolog...