Mass spectrometers measure the mass/charge ratio (m/z) of analytes. Mass spectrometry and MS/MS is applied in protein study as it makes use of the large array of genome and protein data stored in databases. The lists of peak intensities and mass-to-charge (m/z) values produced by a mass spectrometer can be processed and compared with lists generated from the theoretical digestion of a protein or the theoretical fragmentation of a peptide.Mass spectroscopy makes use of the fact that many protein molecules can be adequately displayed on a single gel. This technology was developed in the 1970s, as noted by Klose (1975) and O’Farrell (1975). Identification of the spots separated on these gels remained laborious and was limited to the most abundant proteins until the 1990s, when biological mass spectrometry had developed into a sufficiently sensitive and robust technique.Matrix-assisted laser desorption ionisation (MALDI) employs the use of an excess of matrix material. This matrix is precipitated with the analyte molecules (the analyte contains the galanin molecules to be analysed) by placing a very small volume of the mixture onto a metal substrate and allowing it to dry. This solid is then irradiated by nitrogen laser pulses at a wavelength of 337 nm. The matrix is an organic molecule which absorbs the same wavelength as is emitted by the nitrogen lasers.Galanin, alongside many peptides, uses matrices of dihydrobenzoic acid (DHB) or α -cyano-4-hydroxycinnamic acid. The matrices cause varying degrees of fragmentation because of the different amounts of energies that they give to galanin molecules.The α-cyano-hydroxycinnamic acid matrix is considered to be “hotter” than DHB, and thus leads to a higher sensitivity so the latter is preferred when the ions need to be stable for milliseconds in trapping experiments rather than microseconds in time-of-flight experiments.A liquid containing the galanin analyte is pumped at a low microliter-per-minute flow rate through a hypodermic needle at high voltage to electrospray small droplets; these droplets then evaporate and give their charge onto the galanin analyte molecules. This ionisation process is gentle and is mainly used with molecules that are polar and carry charge. Such molecules include proteins. Increasing the galanin analyte concentration brings out a linear increase in the signal strength. This increase in
Fenn JB, Mann M, Meng CK, Wong SF, 1989. Whitehouse CM. Science 246, pp.64–71.
Gygi S.P., Rist B., Gerber S.A., Turecek F., Gelb M.H. and Aebersold R., 1999. Nat. Biotechnol. 17, pp. 994–999.
Karas M. and Hillenkamp F., 1988. Anal. Chem. 60, pp. 2299–2301.
Klose J. 1975., Humangenetik 26, pp.231–243.
Matthias M.,,Ronald C.H., and Akhilesh P., 2001. Analysis of proteins and proteomes by Mass Spectrometry. Annu. Rev. Biochem. 70, pp.437–473.
O’Farrell P.H., 1975. J. Biol. Chem. 250, pp.4007–4021.
Poritsanos N.J., Mizuno T.M., Lautatzis M.E. and Vrontakis M., 2009. International Journal of Obesity, December, 33(12), pp. 1381-1389.
Singh S.N., Vats P., Shyam R., Suri S., Kumria M.M., Ranganathan S., Sridharan K. and Selvamurthy W., 2001. Nutritional Neuroscience, 4(4), pp. 323-331.
Sunia A. T., William W. and Gary S., 2002. Peptide and Protein analysis with mass spectrometry. Spectroscopy ,16, pp. 15-28.
Vicki H.W, Katheryn A.R, Qingfen Z. and Guilong C., 2005. Mass spectrometry of peptides and proteins. Methods 35, pp. 211–222.
Please type your essay title, choose your document type, enter your email and we send you essay samples