Combination of acid labile detergent and C18 Empore™ disks for improved identification and sequence coverage of in-gel digested proteins

A protocol for improved extraction of peptides from in-gel protein digests, using a combination of the acid labile surfactant, sodium deoxycholate (SDC) and C18 Empore™ membranes, is presented. This approach results in better mass spectrum quality, higher numbers of identified peptide peaks and improved identification scores compared to standard tryptic digestion protocols, or protocols using only SDC or only C18 Empore™ disks. The advantages of the new protocol are demonstrated for two different types of samples: Merino wool intermediate filament proteins and Elaeis guineensis (oil palm) mesocarp proteins.     

Synthesis of esters of α-chloroacetoxy-β,β,β,-trichloroethylphosphonic acids

Summary The synthesis of 11 previously unreported dialkyl esters of -mono-, -di-, and -trichloroacetoxy-,,-trichloroethylphosphonic acids has been effected.     

Electrochemical oxidation of tetramethyl esters of α,α,ω,ω-alcaneteracarboxylic acids

Cyclization of esters of butane-1,1,4,4- and pentane-1,1,5,5-tetracarboxylic acids during electrolysis in methanol in the presence of Nal produces, with a yield of 95%, the esters of cyclobutane-1,1,2,2- and cyclopentane-1,1,2,2-tetracarboxylic acids. Under similar conditions, esters of the highest ,,,-alkanetetracarboxylic acids undergo iodation and hydroxymethylation due to electrical oxidation of methanol to formaldehyde. During electrolysis in methanol in the presence of NaOAc, the esters of ,,,-alkanetetracarboxylic acids undergo effective hydroxymethylation, followed by cyclization into substituted five- and six-member lactones, or tetrahydrofurans when structurally possible.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 10, pp. 2332–2339, October, 1992.     

Pressure dependence of the Grüneisen parameters of KCl,KI, LiF,NaCl, and RbBr

A new expression has been obtained, using the Callaway integral equation for thermal conductivity, which relates the pressure dependence of thermal conductivities, average phonon velocities, and average Grüneisen parameters. Using this technique for the first time, we calculated the pressure dependence of the Grüneisen parameters of KCl, KI, LiF, NaCl, and RbBr at 310 K and zero pressure.     

Preparation, characterization, and catalysis of mecro-catalysts

Because catalysis by metals is a surface phenomenon, many technological catalysts contain small (typically nanometre-sired) supported metal particles with a large fraction of the atoms exposed. Many reactions, such as hydrocarbon hydrogenations, are structure-insensitive, proceeding at approximately the same rates on metal particles of various sizes provided that they are larger than 1 nm and show bulk-like metallic behavior. But the catalytic properties are not known when metal particles become so small that their sizes are indium clusters consisting of several indium atoms. Here the catalytic behavior of precisely defined clusters of just four and six indium atoms on solid supports is shown. It is found that the Ir4 and Ir6 clusters differ in catalytic activity both from each other and from metallic Ir particles.