10027/20513 OV Kryukova OV Kryukova VE Tikhomirova VE Tikhomirova EZ Golukhova EZ Golukhova VV Evdokimov VV Evdokimov GF Kalantarov GF Kalantarov IN Trakht IN Trakht DE Schwartz DE Schwartz RO Dull RO Dull AV Gusakov AV Gusakov IV Uporov IV Uporov OA Kost OA Kost SM Danilov SM Danilov Tissue Specificity of Human Angiotensin I-Converting Enzyme. University of Illinois at Chicago 2016 untagged 2016-05-04 00:00:00 Journal contribution https://indigo.uic.edu/articles/journal_contribution/Tissue_Specificity_of_Human_Angiotensin_I-Converting_Enzyme_/10763024 BACKGROUND: Angiotensin-converting enzyme (ACE), which metabolizes many peptides and plays a key role in blood pressure regulation and vascular remodeling, as well as in reproductive functions, is expressed as a type-1 membrane glycoprotein on the surface of endothelial and epithelial cells. ACE also presents as a soluble form in biological fluids, among which seminal fluid being the richest in ACE content - 50-fold more than that in blood. METHODS/PRINCIPAL FINDINGS: We performed conformational fingerprinting of lung and seminal fluid ACEs using a set of monoclonal antibodies (mAbs) to 17 epitopes of human ACE and determined the effects of potential ACE-binding partners on mAbs binding to these two different ACEs. Patterns of mAbs binding to ACEs from lung and from seminal fluid dramatically differed, which reflects difference in the local conformations of these ACEs, likely due to different patterns of ACE glycosylation in the lung endothelial cells and epithelial cells of epididymis/prostate (source of seminal fluid ACE), confirmed by mass-spectrometry of ACEs tryptic digests. CONCLUSIONS: Dramatic differences in the local conformations of seminal fluid and lung ACEs, as well as the effects of ACE-binding partners on mAbs binding to these ACEs, suggest different regulation of ACE functions and shedding from epithelial cells in epididymis and prostate and endothelial cells of lung capillaries. The differences in local conformation of ACE could be the base for the generation of mAbs distingushing tissue-specific ACEs.