The carbohydrate moiety of human glycophorin in CDG syndrome.

Abstract

Human glycophorin, the major sialoglycoprotein of erythrocyte membranes, was isolated from erythrocytes of healthy individuals and four patients with CDG syndrome. Sugar analysis revealed lower carbohydrate content in three out of four CDG-glycophorin samples. In order to characterize closer the glycosylation differences between glycophorin samples in health and disease, reaction with four biotinylated lectins was performed, using ELISA procedure on polystyrene microplates. Results obtained so far strongly suggest that both N- and O-glycans of glycophorin are affected in CDG syndrome.

Glycophorin A in two patients with congenital dyserythropoietic anemia type I and type II is partly unglycosylated.

“…This is obviously not the case. In another report, however, the differences found by Krotkiewska et al (1999) were very large with GPA from 0 erythrocytes having 40% less of total carbohydrates than that from A or B erythrocytes. So even with only a limited number of samples analyzed we conclude that our results do not confirm those findings.…”

“…Thus, PAS-1 from phenol extracted erythrocyte membranes will be further referred to as GPA. In view of the reports that glycopeptides isolated from GPA from 0N erythrocytes have some excess of unsubstituted N-acetylgalactosamine over those from 0M erythrocytes (Krotkiewski et al, 1997) and that GPA from 0 erythrocytes has much less carbohydrates than that from A or B erythrocytes (Krotkiewska et al, 1999) we evaluated also the effect of these blood groups on carbohydrate molar composition of GPA as determined by the present method. As shown in Table 1 we found that GPA from 0N erythrocytes has indeed more of total N-acetylgalactosamine than that from 0M erythrocytes though, due to a small number of samples analyzed, the difference is barely significant statistically (P = 0.06).…”

Surface Plasmon Resonance (SPR)

“…The latter has been described, i.e. human glycophorin A was shown to be underglycosylated in CDG patients (Krotkiewska et al, 1999;Zdebska et al, 2001).…”

Interaction of glycophorin A with lectins as measured by surface plasmon resonance (SPR).

“…The latter has been described, i.e. human glycophorin A was shown to be underglycosylated in CDG patients (Krotkiewska et al, 1999;Zdebska et al, 2001).…”

“…one N-glycan and about 15 O-glycans per molecule; it has been used in numerous immunochemical and biochemical structural investigations, e.g. (Krotkiewski et al, 1993;1999;Podbielska & Krotkiewski, 2000). GPA contains bisecting N-acetylglucosamine in the N-linked glycan (Yoshima et al, 1980).…”