Аннотация:Angiotensin I-converting enzyme (ACE) is a peptidase widely presented in human tissuesand biological fluids. ACE is a glycoprotein containing 17 potential N-glycosylation sites which canbe glycosylated in different ways due to post-translational modification of the protein in differentcells. For the first time, surface-enhanced Raman scattering (SERS) spectra of human ACE fromlungs, mainly produced by endothelial cells, ACE from heart, produced by endothelial heart cellsand miofibroblasts, and ACE from seminal fluid, produced by epithelial cells, have been comparedwith full assignment. The ability to separate ACEs’ SERS spectra was demonstrated using the lineardiscriminant analysis (LDA) method with high accuracy. The intervals in the spectra with maximumcontributions of the spectral features were determined and their contribution to the spectrum of eachseparate ACE was evaluated. Near 25 spectral features forming three intervals were enough forsuccessful separation of the spectra of different ACEs. However, more spectral information could beobtained from analysis of 50 spectral features. Band assignment showed that several features didnot correlate with band assignments to amino acids or peptides, which indicated the carbohydratecontribution to the final spectra. Analysis of SERS spectra could be beneficial for the detection oftissue-specific ACEs.