Simulation of small molecules, polymers, and proteins in dense solvents is an important class of problems both for processing of materials in liquids and for simulation of proteins in physiologically relevent solvent states. However, these simulations are expensive and sampling is inefficient due to the ubiquitous dense solvent. Even in the absence of the dense solvent, rigorous sampling of the...

The average conformation of a flexible chain molecule in solution is coupled to the local solvent structure. In a dense solvent, local chain structure often mirrors the pure solvent structure, whereas, in a dilute solvent, the chain can strongly perturb the solvent structure which, in turn, can lead to either chain expansion or compression. Here we use Monte Carlo (MC) simulation to study such ...

Cloning and characterization of the gene encoding a solvent-tolerant protease from the haloalkaliphilic bacterium Geomicrobium sp. EMB2 are described. Primers designed based on the N-terminal amino acid sequence of the purified EMB2 protease helped in the amplification of a 1,505-bp open reading frame that had a coding potential of a 42.7-kDa polypeptide. The deduced EMB2 protein contained a 35...

Dinitrophenylation-The amino-terminal residue was determined on. a sample of the peptide before desalting. Approximately 1 pmole of the peptide was submitted to dinitrophenylation for 6 hours with the reaction mixture maintained at pH 8.5 with the aid of a pH stat. The solution was evaporated to dryness and triturated with dry ethyl acetate. Estraction was continued until all the yellow color w...

This study investigates the effects of three branched-chain amino acids (BCAA; valine, leucine, and isoleucine) on the in vitro ruminal fermentation of wheat straw using batch cultures of mixed ruminal microorganisms. BCAA were added to the buffered ruminal fluid at a concentration of 0, 2, 4, 7, or 10 mmol/L. After 72 h of anaerobic incubation, pH, volatile fatty acids (VFA), and ammonia nitro...

The formation constants (log K), of the complexes formed between a number of amino acids(glycine , L-valine and L-alanine) with p-sulfonatocalix [4] arene at varying temperatures (25± 0.1to 65 ± 0.1 °C) in aqueous solutions and at natural pH of p-sulphonato-calix [4] arene (pH=3.2) bymeans of UV-Vis spectrophotometeric technique have been investigated. At this pH the guestmolecule is in its cat...

We discuss the effects of the solvent composition on the helix-coil transition of a polypeptide chain. We use a simple model to demonstrate that improving the hydrogen-bonding ability of the solvent can make the transition less cooperative, without affecting the transition temperature. This effect is very different from other solvent effects which primarily influence the melting transition rath...

Heterogeneous catalytic hydrogenation of cyclohexene, catalyzed by Pt/A1203, was carried out in thirteenvarious solvents (four alcoholic solvents, six aprotic polar solvents and three non polar solvents) at 25 °C.Single-parameter correlations of logk vs. normalized polarity parameter (ETN), hydrogen-bond acceptorbasicity (p), hydrogen-bond donor acidity (a) and dipolarity/polarizibility (it*) d...

The activities of six enzymes which take part in the oxidation of valine by Pseudomonas putida were measured under various conditions of growth. The formation of four of the six enzymes was induced by growth on d- or l-valine: d-amino acid dehydrogenase, branched-chain keto acid dehydrogenase, 3-hydroxyisobutyrate dehydrogenase, and methylmalonate semialdehyde dehydrogenase. Branched-chain amin...