Improved CILAT reagents for quantitative proteomics
摘要:
Improved CILAT reagents have been developed, with which an unprecedented number of protein samples can be measured in high-throughput assays, providing a robust tool for MS-based quantitative proteomics. (C) 2009 Elsevier Ltd. All rights reserved.
Hydrolysis of Phosphotriesters: Determination of Transition States in Parallel Reactions by Heavy-Atom Isotope Effects
作者:Mark A. Anderson、Hyunbo Shim、Frank M. Raushel、W. W. Cleland
DOI:10.1021/ja011025g
日期:2001.9.1
measured by isotope ratio mass spectrometry. Parallel reaction and incomplete labeling corrections were made for both systems. DEPC has a primary (18)O isotope effect of 1.041 +/- 0.003 and a secondary (18)O isotope effect of 1.033 +/- 0.002. The primary (18)O isotope effect for DEmNBP was 1.052 +/- 0.003. These large effects suggest a highly associative transition state in which the nucleophile approaches
interest for pharmaceutical research and biochemistry in general. Here we report a novel synthetic pathway, which selectively introduces 15N and 13C isotopes into the anandamide molecule. This isotopically labeled AEA can be studied conformationally in its native binding condition via solid state NMR. These synthetic procedures can also be adapted to produce radioactive ligands for receptor binding assays
[EN] COMPOUND, DIAGNOSTIC AGENT, NUCLEAR MAGNETIC RESONANCE ANALYSIS METHOD, NUCLEAR MAGNETIC RESONANCE IMAGING METHOD, MASS SPECTROMETRY METHOD AND MASS SPECTROMETRY IMAGING METHOD<br/>[FR] COMPOSÉS, AGENT DE DIAGNOSTIC, PROCÉDÉ D'ANALYSE PAR RÉSONANCE MAGNÉTIQUE NUCLÉAIRE, PROCÉDÉ D'IMAGERIE PAR RÉSONANCE MAGNÉTIQUE NUCLÉAIRE, PROCÉDÉ DE SPECTROMÉTRIE DE MASSE ET PROCÉDÉ D'IMAGERIE PAR SPECTROMÉTRIE DE MASSE
申请人:UNIV KYOTO
公开号:WO2009031712A1
公开(公告)日:2009-03-12
To produce a labeled compound for a selected biological substance not using a radioisotope atom which has a risk of exposure to radioactivity and limitation on handling time but using a stable isotope atom; and that the labeled compound can be measured with good sensitivity separably from naturally occurring compounds of the selected biological substance which are substituted with the stable isotope atom. Choline as a biological substance is labeled by substituting the nitrogen atom of the quaternary ammonium group and all the carbon atoms of the methyl group attached to the nitrogen atom with respective isotopes 15N and 13C and used as a diagnostic agent.
Polymers are concentration-amplified with respect to the monomeric units. We show here that a phosphorylcholine polymer enriched with C-13/N-15 at the methyl groups is self-traceable by multiple-resonance (heteronuclear-correlation) NMR in tumor-bearing mice inoculated with the mouse rectal cancer cell line (colon 26). Preliminary measurements indicated that the present polymeric nanoprobe was satisfactorily distinguished from lipids and detectable with far sub-micromolar spectroscopic and far sub-millimolar imaging sensitivities. Detailed ex vivo and in vivo studies for the tumor-bearing mice administered the probe with a mean molecular weight of 63 000 and a mean size of 13 nm, revealed the following: (1) this probe accumulates in the tumor highly selectively (besides renal excretion) and efficiently (up to 30% of the injected dose), (2) the tumor can thus be clearly in vivo imaged, the lowest clearly imageable dose of the probe being 100 mg/kg or 2.0 mg/20-g mouse, and (3) the competition between renal excretion and tumor accumulation is size-controlled; that is, the larger (higher molecular-weight) and smaller (lower molecular-weight) portions of the probe undergo tumor accumulation and renal excretion, respectively. The observed size dependence suggests that the efficient tumor-targeting of the present probe is stimulated primarily by the so-called enhanced permeability and retention (EPR) effect, that is, size-allowed invasion of the probe into the tumor tissue via defective vascular wall. Self-traceable polymers thus open an important area of magnetic resonance imaging (MRI) of tumors and may provide a highly potential tool to visualize various delivery/localization processes using synthetic polymers.