Enzymes that catalyse group transfer reactions comprise a significant fraction of the human proteome and are a rich source of drug targets because of their role in covalent regulatory cycles. Phosphorylation, glycosylation, sulfonation, methylation and acetylation represent some of the key types of group transfer reactions that modulate the function of diverse biomolecules through covalent modi...

The purple bacterial reaction centre uses light energy to separate charge across the cytoplasmic membrane, reducing ubiquinone and oxidizing a c-type cytochrome. The protein possesses a macroscopic structural two-fold symmetry but displays a strong functional asymmetry, with only one of two available membrane-spanning branches of cofactors (the so-called A-branch) being used to catalyse photoch...

An experimental study of the phase inversion behavior of liquid-liquid dispersion has been conducted in a spray extraction column for systems of toluene / water, n-hexane/water, CCl4/water, toluene /water + glycerol (25 % wt), toluene + CCl4 (25 % wt) / water and toluene / acetic acid (5 % wt)/water. The effects of physical properties, mass transfer and column geometry...

the cycloalkylation of diethyl malonate and ethyl cyanoacetate with alkyl dihalide was investigated by using comminuted potassium carbonate as a base and toluene as a solvent in the presence of hexadecyltrimethylammonium bromide (htmab) as a phase-transfer catalyst, which provided a conventional procedure with the advantage of short reaction period and high product yield. the factors influencin...

In this paper, we studied effect of different parameters including density, viscosity, interfacial tension and solute transfer concentration on phase inversion hold-up. The results showed that change in phase density ratio had no effect on phase inversion hold-up. It also disclosed that the phase viscosity ratio was the most effective parameter affecting phase inversion hold-up and each phase h...

A series of molybdenum(vi) cis-dioxo complexes containing tetradentate salan ligands with different para-substitutions on the phenoxy group have been prepared. These complexes catalyse the oxygen atom transfer reaction between dimethylsulfoxide and triphenylphosphine. During oxo transfer catalysis, the complexes are resistant to formation of catalytically inactive oxo-bridged dimeric Mo(v) comp...

BACKGROUND At present, the conversion of oils to biodiesel is predominantly carried out using chemical catalysts. However, the corresponding lipase-catalysed process has important advantages, which include mild reaction conditions and the possibility of using cheap, low quality feedstocks with a high free fatty acid content. Further increases in the efficiency of the enzymatic process are desir...

the purpose of this study is numerical modeling of temperature variation of phases in a two phase regime in fluidized bed dryers including particles belonging to group d of geldart classification. the mass transfer between phases is not taken into consideration in this modeling which has been assumed in three- dimensional, unsteady, and two-phase regime.to verify the modeling we consider the do...

water for agriculture is one of the most important factors in arid and semi-arid areas and municipal wastewater treatment is an important resource for this purpose. therefore, potential of transfer contaminations is a serious problem regarding use of treated wastewater for agriculture. due to the risk of transfer contaminations through the use of wastewater, the study of transfer microbes in so...

What is it? Protein disulphide isomerase is an enzyme with two interrelated activities: as an oxidoreductase, it can catalyse the formation, reduction and isomerisation of disulphide bonds; and as a polypeptide binding protein, it can function as a molecular chaperone which assists the folding of polypeptides. Transient association of PDI with nascent polypeptides during their folding prevents ...