The endothelium of different organs displays a remarkable heterogeneity, although it presents many common functional and morphological features. However, despite our knowledge of heterogeneity among endothelial cells from different sites, the differences between brain microvascular endothelial cells (BMEC) and coronary microvascular endothelial cells (CMEC) are poorly defined. The aim of this study was to investigate whether BMEC are distinct from CMEC at the protein level. Using the proteomic approach, we comparatively analyzed the proteome of cultured BMEC and CMEC. We reproducibly separated over 2000 polypeptides by using two-dimensional electrophoresis (2-DE) at pH range of 3-10. Using PDQuest software to process the 2-DE gel images, forty-seven protein spots were differentially expressed in the two-endothelial cells. Of these, thirty-five proteins are highly expressed in BMEC, whereas twelve proteins are highly expressed in CMEC. Fifteen proteins in BMEC and seven proteins in CMEC were identified with high confidence by matrix-associated laser desorption ionization time-of-flight mass spectrometer (MALDI-TOF-MS). Our data suggested that BMEC and CMEC were different in several aspects including cytokine and growth-related molecules, stress-related proteins, metabolic enzymes, signal transduction proteins and others. The identification of a set of proteins preferentially expressed in BMEC and CMEC provided new data on the heterogeneity of the endothelium., L. Lu, P.-Y. Yang, Y.-Ch. Rui, H. Kang, J. Zhang, J.-P. Zhang, W.-H. Feng., and Obsahuje bibliografii a bibliografické odkazy
K+-p-nitrophenylphosphatase (K+pNPPase) is the enzyme, which is considered to be involved in K+-dependent hydrolysis of the phosphoenzyme in the reaction cycle of Na+, K+-ATPase. The aim of our present study was to characterize some features of K+pNPPase in homogenates of the rat brain and liver. We determined p-nitrophenylphosphatase (pNPPase) activity in the presence of various ion combinations (Mg 2++K+, Mg2+, K+). We found a higher total pNPPase activity in the brain (0.8±0.079 nkat/mg protein) than in the liver (0.08±0.01 nkat/mg protein). Contrary to the liver, the main part of the total brain activity was K+-dependent. The activity of K+pNPPase was significantly higher in cerebral cortex homogenates (0.86±0.073 nkat/mg protein) in comparison to those of the whole brain (0.57±0.075 nkat/mg protein). The specific K+pNPPase activity was two times higher in the isolated pellet fraction (0.911±0.07 nkat/mg protein), rich in synaptosomes, compared to the whole brain homogenate (0.57±0.075 nkat/mg protein). Our results demonstrate the high activity of K+pNPPase in the brain tissue and its distribution mainly into the pellet fraction, what might indicate a possible role of K+pNPPase in specific structures of the brain, e.g. in synaptosomes., M. Ďurfinová, M. Brechtlová, B. Líška, Ž. Barošková., and Obsahuje seznam literatury