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
The generation of superoxide anion radical (O2.-) in the cytochrome b6f complex (Cyt b6f) of spinach under high-light illumination was studied using electron paramagnetic resonance spectroscopy. The generation of O2.- was lost in the absence of molecular oxygen. It was also suppressed in the presence of NaN3 and could be scavenged by extraneous antioxidants such as ascorbate, β-carotene, and glutathione. The results also indicate that O2.-, which is produced under high-light illumination of the Cyt b6f from spinach, might be generated from a reaction involing 1O2, and the Rieske Fe-S protein could serve as the electron donor in the O2.- production. The mechanism of photoprotection of the Cyt b6f complex by antioxidants is discussed. and M. Sang ... [et al.].