An Efficient Synthesis of 2-Cyclohexene-1-Carboxylic Acid and 2-Cyclopentene-1-Carboxylic Acid

A simple and efficient synthesis of the title compounds by modified Grignard methodology is described.     

Quantitation by fast-atom bombardment/mass-analysed ion kinetic energy spectrometry: kinetic analysis of cyclic nucleotide phosphodiesterase activity

Quantitation of cyclic nucleotide phosphodiesterase activity by means of fast-atom bombardment (FAB) mass spectrometry with mass-analysed ion kinetic energy (MIKE) spectrum scanning is described. Characteristic peaks of the substrate, cyclic AMP, and product, AMP, were identified in positive-ion FAB mass spectra and MIKE scans of the protonated molecules. By spiking enzyme incubates with known quantities of cyclic AMP and AMP and measuring peak heights in the MIKE spectra of both spiked and unspiked samples, the concentrations of cyclic AMP and AMP in solution at the end of a series of enzyme incubations have been estimated. From the data obtained the Km and Vmax of the enzymes were calculated as 181 microM and 28.6 nmol/min respectively, showing excellent agreement with values of the Michaelis constant, Km = 205 microM and the maximum velocity Vmax = 33.2 nmol/min obtained by radioactive assay.     

A finite element method for the solution of two-dimensional transonic flows in cascades

Steady two-dimensional transonic flow is calculated in cascades of compressor and turbine blades using a mesh of triangular finite elements. A velocity potential is used, the equations being solved by the Newton-Raphson technique. The resulting computer program is fast, and is shown to give good accuracy. Shock waves are well represented, provided they are not too strong.     

Online immobilized metal affinity chromatography/mass spectrometric analysis of changes elicited by cCMP in the murine brain phosphoproteome

An automated online immobilized metal affinity chromatography/high‐performance liquid chromatography mass spectrometric (IMAC‐HPLC/MS/MS) method was developed to study cytidine 3′,5′‐cyclic monophosphate (cCMP)‐specific protein phosphorylation, analogous to a previously successful offline IMAC method using microvolume IMAC pipette tips. The optimized method identified murine brain phosphoproteins selectively modified by challenge with cCMP, using manual interpretation of the results to confirm both phosphorylation and selectivity of response to cCMP. A number of proteins identified by this strategy have potential roles in hyperproliferation, a previously reported response to elevated levels of cCMP. Copyright © 2008 John Wiley & Sons, Ltd.     

Quantitation by fast-atom bombardment mass spectrometry: assay of cytidine 3',5'-cyclic monophosphate-responsive protein kinase.

A protein kinase, stimulated by cytidine 3',5'-cyclic monophosphate, is conventionally assayed by monitoring the incorporation of radiolabelled phosphate from adenosine triphosphate into a histone substrate. Here the assay of the protein kinase is carried out by positive-ion fast-atom bombardment mass spectrometric analysis of the enzyme incubation mixture after the reaction has been terminated. The data so obtained show good agreement with data obtained by the conventional radiometric assay: the intrinsic advantage of the mass spectrometric assay is the capacity for multiple component monitoring; the ability of the kinase to bind competing cyclic nucleotides together with integral adenosine triphosphatase (ATPase) and phosphodiesterase activity can also be assessed.     

Synthesis amd characterization of [Et4,N]2[Mo(CO)4(SR)2] (R = Ph,Bz): New,potentially chelating bis-thiolate species

The new complexes [Et₄N]₂ [Mo(CO)₄(SR)₂] (R = Ph, Bz) have been prepared by reaction of [Et₄N] [SR] with (norbornadiene)Mo(CO)₄ at low temperature. The IR spectra and electrochemical behavior of these two species are different, perhaps implicating different conformational isomers with respect to the thiolate ligands. These complexes may prove to be valuable reagents for the synthesis of new heterometallic compounds, by virtue of their cis-monodentate thiolate ligands.