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Date: 11-3-2020
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Date: 5-3-2020
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Date: 3-3-2020
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Proteins and peptides have been characterized by high pressure liquid chromatography (HPLC) or SDS PAGE by generating peptide maps. These peptide maps have been used as fingerprints of protein or as a tool to know the purity of a known protein in a known sample. Mass spectrometry gives a peptide map when proteins are digested with amino end specific, carboxy end specific, or amino acid specific digestive enzymes. This peptide map can be used to search a sequence database to find a good match from the existing database. This is because the more accurately the peptide masses are known, the less chance there is of bad matches.
Electron spray ionization coupled to triple quadrupole (TSQ) and ion trap mass spectrometers (ITMS) and matrix assisted laser desorption ionization (MALDI) coupled to time of flight (TOF) analyzers have been successful for obtaining very accurate mass measurements. TOF, TSQ, and ITMS can give mass accuracies better than 0.1. MALDI-TOF mass spectra (MS) is a good tool for screening peptide masses of tryptic digests. This method is more effective because it requires relatively less intense sample preparation since the matrix is less susceptible to interferences caused by salts and detergents. Secondly MALDI-TOF-MS generates peptides containing only one charge and show only one peak in spectrum which facilitates data interpretation.
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دراسة يابانية لتقليل مخاطر أمراض المواليد منخفضي الوزن
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اكتشاف أكبر مرجان في العالم قبالة سواحل جزر سليمان
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المجمع العلمي ينظّم ندوة حوارية حول مفهوم العولمة الرقمية في بابل
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