Analysis of Galanin Using Mass Spectrometry Essay

Analysis of Galanin Using Mass Spectrometry - Essay Example It is reported that obese human beings have been observed to have high levels of serum galanin; this suggests that peripheral galanin has a role to play in the regulation of balance of energy and that high circulating galanin levels are a contributing factor to the development of obesity and obesity-related metabolic impairments. In their findings, they report that high levels of galanin in the serum can help regulate body weight, metabolic rate and carbohydrate-lipid metabolism through a mechanism that does not depend on the feeding regulation Galanin may also be responsible for high altitude induced anorexia. Singh et al. (2001) carried out studies on the roles played by galanin and neuropeptide Y in high altitudes in food uptake. Male Sprague-Drawley rats were exposed to conditions mimicking those at a high altitude of 7620 meters for 1, 7, 14 and 21 days for a six-hour period each day and to an altitude of 6096 meters for a continuous 72 hours to study the effects of intermittent and continuous exposure. Galanin and neuropeptide Y levels were estimated in various parts of the brain and plasma of exposed and unexposed rats. They found that plasma galanin levels decreased in both groups of rats. They asserted that the changes in the levels of galanin may be responsible for anorexia at high altitudes. Galanin signaling occurs through three G protein-coupled receptors. After mucosal stomach biopsies, the galanin can be analyzed using mass spectrometry. The technique Mass spectrometry involves measuring the mass of a compound, this with very high sensitivity. Mass spectrometers require molecules to be charged and in gaseous form for analysis. Peptide molecules in galanin being large and polar, are not easily transferred into the gas phase and ionised. Electrospray (ES) Fenn et al (1989) and matrix-assisted laser desorption ionization (MALDI) Karas and Hillenkamp (1988) are the ionization techniques that are used to transform the galanin into the gas-phase. 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. In the analysis of galanin using mass spectroscopy: 1. The galanin sample will undergo vaporisation to transform i t into a gaseous form. 2. The gaseous form will then be bombarded by an electron beam to generate ions. 3. The generated ions are them separated depending on their mass-to-charge ratio by an electromagnetic field in an analyser. The analyser can be Time of Flight (TOF) or a quadruple ion trap. 4. The ions are detected. 5. The ion signal is processed into mass spectra. Ionization techniques 1. Matrix-assisted laser desorption ionisation MALDI 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