Laser desorption mass spectrometry, enzymatic

Xu, S., Pan, C., Hu, L., Zhang, Y, Guo, Z., Li, X., Zou, H. Enzymatic reaction of the immobilized enzyme on porous silicon studied by matrix assisted laser desorption/ionizationtime of flight-mass spectrometry. Electrophoresis 2004, 25, 3669-3676. 

Below we report methodological studies based upon HPLC, GC/FID, GC-MS, LC-MS, matrix-assisted laser desorption ionisation coupled with time-of-flight mass spectrometry (MALDI-ToF/MS), CE, proton nuclear magnetic resonance ( I INMR), RIA and enzymatic colorimetric techniques. 

KL O Connell, JT Stults. Identification of mouse liver proteins on two-dimensional electrophoresis gels by matrix-assisted laser desorption/ionization mass spectrometry of in situ enzymatic digests. Electrophoresis 18 349-359, 1997. 

Recently, MALDI-TOF (matrix-assisted laser desorption/ionisation-reflection time-of-flight) mass spectrometry was introduced as a new approach for the investigation of pellicle composition [39], Using mass spectrometry for compositional analysis, it was found that more intact salivary protein species were present in an in vitro-formed pellicle compared to an in vivo-formed pellicle [39], This finding suggests that the in vivo pellicle is an entity formed with components undergoing more extensive enzymatic (proteolytic) processing than in the in vitro pellicle. Therefore, in vitro-formed pellicle layers cannot completely mirror what occurs within the oral cavity [39], This difference may be due to differences in the proteolytic capacity of the saliva supernatant used for in vitro pellicle formation and that of the oral environment. In addition, a particular saliva sample used for in vitro pellicle formation is a closed system, whereas the oral environment is an open system with continuous influx and clearance of oral fluids [39]. 

PCL was also degraded to 6-hydroxyhexanoic acid during enzymatic hydrolysis by Lipase Asahi derived from Chromobacterium viscosum and Hp-ase F derived from Rhizopus niveus [74]. In another study formation of oligomers during biotic hydrolysis of PCL was shown by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) [50]. Enzymatic degradation of copolymers of 3-hydroxybutyric acid (3HB) and... 

T. A. Shaler, Y. Tan, J. N. Wickham, K. J. Wu, and C. H. Becker, Analysis of enzymatic DNA sequencing reactions by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, Rapid Commun. Mass Spectrom. 9, 942-947 (1995). 

Liao, P.C., Leykam, J., Andrews, P.C., Gage, D.A., and Allison, J. (1994) An approach to locate phosphorylation sites in a phosphoprotein mass mapping by combining specific enzymatic degradation with matrix-assisted laser desorption/ionization mass spectrometry. Anal. Eiochem., 219, 9-20. 

S., Karas, M., and HiUenkamp, F. (1994) Matrix assisted laser desorption/ ionization mass spectrometry of enzymatically synthesized RNA up to 150kDa. Nucleic Acids Res., 22 (19), 3866-3870. 

Experimental design of time-resolved mass spectrometry (TRMS) systems can greatly affect temporal resolution in the analysis of dynamic samples (see also Section 4.2). The two popular MS approaches - laser desorption/ionization (LDI)-MS and electrospray ionization (ESI)-MS - are suitable for studies of enzymatic reactions [8]. 

The sensitive requirements for exposure assessment have been met by the recent development of mass spectrometry (MS) techniques for the characterisation of proteins expressed by a genome, tissue or cell. Of particular interest is the matrix-assisted laser-desorption/ionisation (MALDI), which makes it possible to obtain protein mass fingerprinting for a wide range of proteins by MS. This method involves selectively cutting proteins by enzymatic actions, and comparing the fragment masses with theoretical peptides available in bio-informatic databases. 

Bald2ovd T, Sedo O, Stefanid P, et al. Improvement in Staphylococcus and Bacillus strain differentiation by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry profiling by using microwave-assisted enzymatic digestion. Rapid Commun Mass Spectrom. 2014 28 1855-61. doi 10.1002/rcm.6966. 

FIGURE 10 J Molecular weight and polydispersity changes during the course of enzymatic polymerization of 4-phenylphenol as a function of the amount of added. Reprinted (adapted) with permission form Xu P, Kumar J, Samuelson L, Cholli AL. Monitoring the enzymatic polymerization of 4-phenylphenol by matrix-assisted laser desorption ionization time-of-flight mass spectrometry a novel approach. Biomacromolecules 2002 3 889-893. 2002 American Chemical Society. 

Abstract Mass spectrometry is the most sensitive and specific analytical technique available for protein identification and quantification. Over the past 10 years, by the use of mass spectrometric techniques hundreds of previously unknown proteins have been identified as DNA-binding proteins that are involved in the regulation of gene expression, replication, or DNA repair. Beyond this task, the applications of mass spectrometry cover all aspects from sequence and modification analysis to protein structure, dynamics, and interactions. In particular, two new, complementary ionization techniques have made this possible matrix-assisted laser desorption/ionization and electrospray ionization. Their combination with different mass-over-charge analyzers and ion fragmentation techniques, as well as specific enzymatic or chemical reactions and other analytical techniques, has led to the development of a broad repertoire of mass spectrometric methods... 

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