DI-MS Technique for Analyzing Protein and Peptide Sequences

DI-MS Technique for Analyzing Protein and Peptide SequencesFood Industrial ApplicationDI-MS technique has been widely applied in food industry as it is an easy and towering-throughput tool for analyzing protein and peptide sequences, studying the components or complex body part in food, monitoring the contamination in food.FAB-MSIn the study by Terzi, Boyot, Dorsselear, Luu and Trifilieff (1990), the amino erosive sequence of a new 6.8 kDa proteolipid from beef heart was determined by employed FAB-MS. The study quarantined and purified the 6.8 kDa proteolipid from an irateic methanol/chloroform extract of bovine cardiac muscle, and subsequently analyzed it with the application Cs atom beam of FAB-MS in 1-thioglycerol matrix. The result showed a protonated molecular ion M+H+ at m/z 6834.1 and indicated that it be possessed of about 60 residues. The 60 residues in the polypeptide were cleaved into third peptide fragments CN1, CN2 and CN3. To characterize these cleavage peptides from amino acid patch, the CN1 and CN2 were ionised development the FAB-MS that performed with Xe atom beam and 1-thioglycerol matrix spot the CN3 which also dissolved in 1-thioglycerol was collided by Cs atom beam to produce sample ions.Table 1.0 Chemical mass of cleavage peptides sectionalizationpeptidesMeasured massM+H+M+Na+CN11539.01560.9CN22100.52121.8CN33134.6From the digest of the cleavage peptides, the amino acid sequence and peptide fragments of the 6.8 kDa proteolipid were account asMLQSLIKKVWIPMKPYYTQAYQEIWVGTGLMAYIVYKIRSADKRSKALKASS1 CN1 13 14 CN2 31 32 CN3AAPAHGHH60In addition, the FAB-MS technique was applied to determine the structure of the Lycium chinense Miller fruits (Gou-Qi-Zi) in combination with NMR and IR spectroscopy (Chung, Ali, Praveen, Yu, Kim, Ahmad, 2014). L. chinense fruit is a invaluable tonic or food, hence there are many researches have been reported to display the properties the L.chinense fruit. For example, the anticancer, antibacterial d rug and antioxidant properties (Lee et al., 2005 Wang, Chang, Inbaraj. Chen, 2010 Zhang et al., 2011) and the antihepatotoxic activity and chemical constituents (Chin et al., 2003 Kim et al., 1997).In the research, the quadruple new compounds (i, ii, iii and iv) that isolated from L. chinense fruits were characterized using the FAB-MS (JMS-700) spectrometer. The antioxidant activity of the four compounds was further studied and it demonstrated that the activity of the compounds followed the order 1423.Table 2.0 Characterization of compound (i) to (iv)Mass Speciesm/zDetected speciesSuggestionCompound (i)M+H+817C40H65O17-aromatic acid glycosidic ester283CH3(CH2)16COO+-steric acid was esterified with one phenolic group267CH3(CH2)16CO+414C15H26O13+-three arabinose unit of measurements amaze to one phenolic group265C10H17O8+133C5H9O4+Compound (ii)M+H+1165C50H85O30-susquiterpene glycoside ester265C10H17O8+-few arabinose units bind to the sesquiterpene moiety223C14H27CO+133C5H8O5+Compo und (iii)M+1309C58H100O32-hexaglycoside341C12H21O11+-six hexose sugar units bind to separately other-unsaturated fatty acid located at terminal position335C21H39COO+325C12H21O10+319C12H39CO+179C6H11O6+163C6H11O5+Compound (iv)M+H+841C31H52O26-five arabinose units and one glucose unit661C25H41O20+-five pentose sugar units bind to a hexose sugar529C25H41O20-C5H8O4+281C10H17O9+TOF-SIMSTOF-SIMS which widely applied in surface analysis is an definitive technique for monitoring the contamination in food as the usage of pesticides and fungicide in the agribusiness practice will alter and compromise the food quality. The study used TOF-SIMS technique to characterize and comparing three different groups of Seggianese olives which classified as un hardened (UT), treated with insecticide (dimethoate) and fungicide (copper oxychloride) without washing (TU) and treated with insecticide and fungicide with washing with cold water (TW) (Focardi, et al., 2006).Before measuring the molecular masses of three different groups of olives, the mass calibration was done by using CH3+, C2H3+ and C3H5+ peaks as calibration compounds for positive ions C, CH and C2H peaks as calibration compounds for negative ions. The SIMS data proved the chemical treatments modify the surface composition of olive, resulting in high intensity signals in TU compared with TW or UT olive spectra. Besides, the intensity of UT and TW olives showed a small fluctuation between each other, demonstrating the washing process was no effective in removing of insecticides and fungicides that will stimulate the composition alterations of olives.Table 3.0 Intensity of few relevant peaks from three different olive samplesPeaksMass peakm/zAttributionIntensityTU oliveTW oliveUT olivePositive31.018CH3O+4.23 10-46.93 10-51.12 10-457.074C4H9+1.18 10-25.92 10-35.08 10-373.051C4H9O+7.83 10-43.34 10-43.08 10-4147.082C6H14NOP+ /C6H13NOS+2.42 10-47.37 10-52.93 10-5Negative15.994O1.13 10-42.30 10-37.20 10-317.0 02OH1.19 10-44.42 10-35.44 10-331.972S5.24 10-41.99 10-51.47 10-5MALDI-TOF/TOF MSMALDI-MS is a widespread analytical tool for proteins, peptides and oligonucleotides as it offers high ion yields of the intact analyte samples, high sensitivity and accuracy (Lewis, Wei, Siuzdak, 2000). In year 2012, a research about the peptide of peanut hydrolysate has the properties of umami taste had reported by Su, Cui, Zheng, Yang, Ren Zhao. Umami taste is known as the fifth basic taste and it usually described as savory or MSG-like taste. In the study, two novel umami and umami-enhancing peptides were isolated from peanut hydrolysate, purified using chromatography and identified by MALDI-TOF/TOF MS.The analysis of peptides was performed by MALDI-MS equipped with 337nm of UV nitrogen laser and matrix solution as sinapic acid saturated in 0.1% trifluoroacetic acid and acetonitrile. The MALDI-TOF/TOF MS was used to sequence the two novel peptides that termed as P3 and P4 as they produce uma mi taste. It found that the molecular mass of P3 and P4 was 1091.419 Da and 965.595 Da respectively and the amino sequence of P3 is EGSEAPDGSSR while P4 is SSRDEQSR.BibliographyChung, I. M., Ali, M., Praveen, N., Yu, B. R., Kim, S. H., Ahmad, A. (2014). New polyglucopyranosyl and polyarabinopyranosyl of fatty acid derivatives from the fruits of Lycium chinense and its antioxidant activity. Food Chemistry, 435-443.Focardi, S., Ristori, S., Mazzuoli, S., Tognazzi, A., Leach-Scampavia, D., Castner, D. G., et al. (2006). ToF-SIMS and PCA studies of Seggianese olives and olive oil. Colloids and Surfaces, 225-232.Lewis, J. K., Wei, J., Siuzdak, G. (2000). Matrix-assited laser desorption/iomization mass spectrometry in peptide and protein analysis. Chichester John Wiley Sons Ltd.Su, G., Cui, C., Zheng, L., Yang, B., Ren, J., Zhao, M. (2012). isolation and identification of two novel umami and umami-enhancing peptides from peanut hydrolysate by consecutive chromatography and MALDI-TOF/ TOF MS. Food Chemistry, 479-485.Terzi, E., Boyot, P., Dorsselear, A. V., Luu, B., Trifilieff, E. (1990). Isolation and amino acid sequence of a novel 6.8-kDa mitochondrial proteolipid from beef heart. FABS Letters, 122-126.ConclusionIn food industry, the analysis of protein and peptide can be performed well by using MALDI-MS and FAB-MS while the application of SIMS is mostly used for discover the surface of contaminated food. Besides, the structure of the components in foods can also be identified by using the FAB-MS combined with NMR and IR spectroscopies.