The proton nuclear magnetic resonance spectra of several chloroperoxidase-inhibitor complexes have been investigated. Titrations of chloroperoxidase with azide, thiocyanate, cyanate, or nitrite ions indicate that only the chloroperoxidase-thiocyanate complex exhibits slow ligand exchange on the 360-MHz NMR time scale. The temperature dependence of the proton NMR spectra of the complexes suggest...

Intrinsic spin lattice relaxation times for the hyperfine-shifted exchangeable resonances and the downfield heme methyls for the low spin met-cyano-, met-nicotinate-, and deoxy- complexes of soybean leghemoglobin a were determined in H2O. When exchange with the bulk solvent is slow on the T1 time scale, comparison of the intrinsic T1 values for the exchangeable protons and the heme methyl reson...

A series of fluorinated sulfonated poly (ether amide)s (SPAs) were synthesized for proton exchange membrane fuel cell applications. A polycondensation reaction of 4,4’-oxydianiline, 2-sulfoterephthalic acid monosodium salt, and tetrafluorophenylene dicarboxylic acids (terephthalic and isophthalic) or fluoroaliphatic dicarboxylic acids produced SPAs with sulfonation degrees of 80–90%. Controllin...

A theoretical procedure of measuring the resistance offered by a proton exchange membrane to proton flow through it has been outlined. The process has been modeled using simple mass transfer laws and electrical analogies. The final result showed that a second order differential equation, incorporating the membrane resistance, described the process completely. A major assumption that has been ma...

Proton-transfer reactions across and at the surface of biological membranes are central for maintaining the transmembrane proton electrochemical gradients involved in cellular energy conversion. In this study, fluorescence correlation spectroscopy was used to measure the local protonation and deprotonation rates of single pH-sensitive fluorophores conjugated to liposome membranes, and the depen...

Jatropha curcas oil is one of interesting renewable resources for preparation biolubricants. However, direct application this as a biolubricant restricted due to its low oxidative stability. This drawback can be overcome by molecule structural redesign through chemical modification process at unsaturated functional groups. was modified via epoxidation, ring opening and esterification processes....

NMR investigations have been carried out of complexes between bovine chymotrypsin Aalpha and a series of four peptidyl trifluoromethyl ketones, listed here in order of increasing affinity for chymotrypsin: N-Acetyl-L-Phe-CF3, N-Acetyl-Gly-L-Phe-CF3, N-Acetyl-L-Val-L-Phe-CF3, and N-Acetyl-L-Leu-L-Phe-CF3. The D/H fractionation factors (phi) for the hydrogen in the H-bond between His 57 and Asp 1...

Lipmann and Tuttle (1) discovered that certain bacterial extracts catalyze a rapid interchange of inorganic and acetyl-bound phosphate. They suggested that this exchange might be due in part to a reversibility of the phosphoroclastic decomposition of pyruvate; however, the observation that the exchange was surprisingly unaffected by addition of acetyl acceptors like formate led them to suspect ...

Proton relay plays an important role in many biocatalytic pathways. In order to mimic such processes in the context of molecular switches, we developed coordination-coupled deprotonation (CCD) driven signaling and signal enhancement sequences. This was accomplished by using the zinc(ii)-initiated CCD of a hydrazone switch to instigate an acid catalyzed imine bond hydrolysis that separates a que...