Characterization of small molecular weight rat urine proteins

In this study was made to investigate small molecular weight proteins and their isoforms were invetigated in male Wistar rat urine. Two healthy Wistar rats were used for the experiments. Proteins found in the urine of rats were separated and purified with the two-dimensional gel electrophoresis technique. Out of the small molecular weighted proteins found in the urine samples twenty nine of the spots visualised on two dimensional gels were identified. For identification of them MALDI-TOF mass spectrometry was used. Measuring masses we will get peptide mass fingerprint spectra for each spot. Proteins found in the spots were identified using the data reached from the spectra by searching in the protein database MASCOT. 19 spots matched with ?2u-globulin and the other 10 spots matched with various other proteins. Because most of the proteins matched with ?2u-globulin, it was examined in which sequence they are. For this examination the NCBI (National Center for Biotechnology Information) database was used. It was tried to determine the sequences matching with the proteins found in the spots according to the 15 recorded sequences for the ?2u-globulin protein with aminoacid differences. According to the detected peptide peaks in the spectra, for each spot separation of possible protein izoforms within different sequences could be done. For a lot of spots the PMF results were supported with the MS/MS results taken for selected peptides.