Carcinoembryonic Antigen, Its Spatial Structure and Localization of Antigenic Determinants

Abstract

The effects of temperature and pH on the spatial structure of carcinoembryonic antigen (CEA) and its various derivatives are studied by circular dichroic spectroscopy and differential UV spectroscopy. The spatial organization of the protein portion of CEA and its derivatives as revealed by spectroscopic evidence is discussed with respect to the antigenic activity of the species studied. We conclude that the protein portion of CEA consists mainly of a β-structural type. Using the various modifications of the sugar moiety and the protein portion, antigenic determinants of CEA are shown to possess the main conformational character of the molecule while participation of the sugars in the formation and orientation of the carbohydrate chains relative to the protein core of the antigen appear to be important.

Extended Glycoprotein Structure of the Seven Domains in Human Carcinoembryonic Antigen by X-ray and Neutron Solution Scattering and an Automated Curve Fitting Procedure: Implications for Cellular Adhesion

“…The full analysis indicated that an average oligosaccharide chain contained 3.1 Man, 5.5 GlcNAc, 3.1 Gal and 2.7 Fuc residues. The sialic acid content per oligosaccharide chain was estimated to be 0.6 (Chandrasekaran et al, 1983;Slayter & Coligan, 1975;Hammarströ m et al, 1975;Kessler et al, 1978;Pavlenko et al, 1990). The CEA carbohydrate was therefore represented by 28 trianntenary complex-type oligosaccharide chains of composition Man3GlcNAc6Gal3Fuc3NeuNAc1, which were located at putative NXT or NXS sites in the CEA sequence (except when X = Pro).…”

Parity-time symmetry based on resonant optical tunneling effect for biosensing

“…On the other hand, assuming the cross-section of gain cavity is 0.25 cm 2 , if 1 g CEA is all deposited on the gain cavity, its thickness would be 3 cm (the density is about 1.35 × 10 3 kg/m 3 ). As the molar extinction coefficient of CEA is 1×10 5 M -1 cm -1 [52], the absorption of CEA per unit length (1 cm) is 3.3 × 10 4 cm -1 (not including optical scattering or dispersion). Based on the simulation results, the minimum thickness of CEA can be detected is 1.13×10 -10 cm, which corresponds to 0.4 ng (equivalent to 2.2 fmol).…”

Bioglycans and Natural Glycosides As a Promising Research Topic in Bioorganic Chemistriy

“…In this relation, the carcino–embryonic antigen ( CEA ) [ 63 , 64 ], which does not differ in high specificity and is not revealed in the bodily fluids of a healthy human, is of great interest. Its appearance and accumulation in blood (more than 5 ng/ml) evidence the presence of almost any oncological disease in the organism, like neoplasias of the digestive tract and respiratory system or carcinoma of the breast, head, or neck [ 63 ].…”

“…Like all the oncofetal antigens CEA is a complicated glycoprotein, the protein part of which plays the determinative role. A study of its spatial structure showed that the carbohydrate moiety stabilizes the CEA conformation [ 64 , 65 ].…”