Krysteva M.Mancheva I.Dobrev I.2024-07-102024-07-102024-07-102024-07-101973-01-011432-10330014-295610.1111/j.1432-1033.1973.tb03180.xSCOPUS_ID:0015724088https://rlib.uctm.edu/handle/123456789/46The particular environments of tyrosine side chains were suggested to be responsible for the non‐denaturation acidic difference spectra of ovomucoid as well as of abnormal ionization of its phenolic groups. The micro environment of the most exposed tyrosine in ovomucoid was studied. The tyrosine was first labelled by means of tetranitromethane. Nitrotyrosine peptide was isolated. The study of the nine steps of nitrotyrosine peptide degradation results in the following amino acid sequence: Ala‐Gly‐Ala‐Lys‐Thr‐Gln‐NO2Tyr‐Gly‐Gly. The analysis of neutral sugars as well as glycosamine gave negative results. The presence of sialic acid however was detected. On the basis of evidence obtained, the existence of a glycosidic bond formed from the hydroxyl group of tyrosine and the glycosidic hydroxyl group of sialic acid was suggested. The spectral behaviour of the tyrosine studied was discussed in the light of above assumption. Copyright © 1973, Wiley Blackwell. All rights reservedenArticle