Comparison of Different Experimental Conditions for Blood Proteomic Distinguishing Using MALDI-TOF MS

The goal of this pilot work was to find out suitable experimental conditions which enable to reliably determine the species origin of blood by proteomic analysis using Matrix-Assisted Laser Desorption/Ionization – Time of Flight Mass Spectrometry. Easy and quick determination of the presence of blood and its animal species determination is useful, for example, for uncovering incorrectly marked or adulterated meat in the food industry, fighting against illegal hunting, and for the analysis of art objects. The main advantage of the proteomic approach over DNA analysis is the long-term durability of proteins and usually their greater quantity in the sample. The tested conditions included searching for the most suitable time duration of trypsin cleavage of blood proteins, monitoring the effect of removal of blood lipids on trypsin cleavage, and the determination of a suitable solution for trypsin cleavage (isopropanol at various concentrations or ۵۰ mM NH۴HCO۳). Obtained mass spectra were processed by Principal Component Analysis and m/z values specific for humans and six other selected animal species (cat, chicken, cow, dog, goose, human, and pig) were found. It was possible to divide blood samples of all analysed avian and mammalian species into separate clusters and to identify the species origin of an unknown sample using Principal Component Analysis. The animal species origin of the unknown sample was confirmed by the species-specific m/z values and Partial Least Squares – Discrimination Analysis.

کلیدواژه ها:

Animal blood ، Blood proteins ، Characteristic m/z values ، Mass spectrometry ، Principal component analysis (PCA) ، Tryptic cleavage