Matrix-assisted laser desorption with time

Matrix-assisted laser desorption with time of flight (MALDI-TOF)... 

Considering these situations, the observation of molecular weights, particularly by matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI-TOF MASS), is essential [33]. The operation is simple and enables us to observe the molecular ion peaks of CPOs with molecular weights exceeding 10,000. The quahty of the measurement is strongly dependent on the choice of the matrix. Therefore, the search for the best matrix for each CPO should be pursued. 

Choudhary, G., Chakel, J., Hancock, W., Torres-Duarte, A., McMahon, G., and Wainer, I., Investigation of the potential of capillary electrophoresis with offline matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for clinical analysis examination of a glycoprotein factor associated with cancer cachexia, Anal. Chem. 71, 855, 1999. 

Madonna, A. J. Van Cuyk, S. Voorhees, K. J. Detection of Escherichia coli using immunomagnetic separation and bacteriophage amplification coupled with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Rapid Comm. Mass Spectrom. 2003,17, 257-263. 

Arnold, R. J. Reilly, J. P. Fingerprint matching of E. coli strains with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of whole cells using a modified correlation approach. Rapid Commun. Mass Spectrom. 1998,12,630-636. 

Proteomics ultimately hinges upon protein identification to reveal the meaning behind the masses, spots, or peaks detected by other means. Because fraction collection is a natural component of HPLC separations, intact proteins can be readily collected either for direct analysis or for proteolytic digestion and identification using peptide mass fingerprinting (PMF) in conjunction with matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). 

A modified version of 2DE and gel image analysis, with silver staining, autoradiography, and protein identification and measurement of peptide mass, uses matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) as a rapid and sensitive technique for identifying peptides. MALDI-TOF-MS applies well to protein detection in biological fluids.56 A second advantage of this technique is... 

The development glycopeptide libraries obtained by the split-mix method is severely hampered by the lack of concurrent development of a general, facile separation and characterization technology. Some headway has been made with chemical coding of the libraries, but very few direct methods of analysis exist. One promising method that could be applied to the direct characterization of both types of libraries is mass spectrometry. More specifically, post-source-decay matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (PSD-MALDI-TOF-MS) and CID-FAB/MS/MS have been used to characterize glycopeptides.53-55... 

Chakel, J. A., Erno, J., Hancock, W. S., and Swedberg, S. A. (1997). Analysis of recombinant DNA-derived glycoproteins via high-performance capillary electrophoresis coupled with off-line matrix-assisted laser desorption ionization time-of-fiight mass spectrometry. /. Chromatogr. B 689, 215—220. 

Page, J. S., Rubakhin, S. S., and Sweedler, J. V. (2000). Direct cellular assays using off-line capillary electrophoresis with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Analyst 125, 555-562. 

The product was identihed by a number of spectroscopic methods. Dioxygen uptake was measured by spectrophotometric titration. MALDI-TOF-MS (matrix-assisted laser desorption/ionization-time of flight-mass spectrometry), an MS method particularly suited to determining molecular masses of biopolymers and synthetic materials with relative masses up to several hundred kilodaltons, determined that the product contained stoichiometric amounts of the heme starting material, the copper complex, and dioxygen in a 1 1 1 ratio. 

There are at least three possibile ways in which the inhibitor can bind to the active site (1) formation of a sulfide bond to a cysteine residue, with elimination of hydrogen bromide [Eq. (10)], (2) formation of a thiol ester bond with a cysteine residue at the active site [Eq. (11)], and (3) formation of a salt between the carboxyl group of the inhibitor and some basic side chain of the enzyme [Eq. (12)]. To distinguish between these three possibilities, the mass numbers of the enzyme and enzyme-inhibitor complex were measured with matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI). The mass number of the native AMDase was observed as 24766, which is in good agreement with the calculated value, 24734. An aqueous solution of a-bromo-phenylacetic acid was added to the enzyme solution, and the mass spectrum of the complex was measured after 10 minutes. The peak is observed at mass number 24967. If the inhibitor and the enzyme bind to form a sulfide with elimination of HBr, the mass number should be 24868, which is smaller by about one... 

Matrix assisted laser desorption ionization time-of-flight (MALDI-TOE) mass spectrometry was carried out with a PerSeptive Biosystems Voyager-DE-RP MALDl-TOF mass spectrometer. A 337-nm UV nitrogen laser producing 3-ns pulses was used in the reflectron mode. The samples were prepared by mixing 10 pi of a 0.1 M HAc solution of the sample with 20 pi of a solution of 3 mg/1 a-cyano-4-hydroxy cinnamic acid in wafer. One pi of that solution was loaded on the gold-sample plate. 

Together with ESI MS, other soft ionization MS techniques, such as matrix-assisted laser desorption/ionization time of flight (MALDI TOF) and fast atom bombardment (FAB) MS, may be used for the determination of the stoichiometry of selector-selectand complexes. 

Even if relatively new, HF FIFFF has been used to separate supramicrometer particles, proteins, water-soluble polymers, and synthetic organic-soluble polymers. Particle separation in HF FIFFF has recently been improved, reaching the level of efficiency normally achieved by conventional, rectangular FIFFF channels. With these channel-optimized HF FIFFF systems, separation speed and the resolution of nanosized particles have been increased. HF FIFFF has recently been examined as a means for off-line and on-line protein characterization by using the mass spectrometry (MS) through matrix-assisted laser desorption ionization time-of-flight mass spectrometry (M ALDl-TOF MS) and electrospray ionization (ESl)-TOF MS, as specific detectors. On-line HF FIFFF and ESl-TOF MS analysis has demonstrated the viability of fractionating proteins by HF FIFFF followed by direct analysis of the protein ions in MS [38]. 

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