Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P02749 (beta2-glycoprotein I)
 836 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The synthesis of various products by a human mammary cell line (BT 20) was studied by incorporation of 14C-labeled amino acids, choline, glucosamine, or galactosamine into nondialyzable materials. These products had molecular weights ranging from less than 12,300 daltons to more than 200,000 daltons. They were analyzed by immunoelectrophoresis and double diffusion in agar. Among the synthesized products, the following proteins were identified: beta2-glycoprotein I, alpha2HS-glycoprotein, alpha2-lipoprotein, actin, beta2-microglobulin, carcinoembryonic antigen, three oncofetal-associated antigens, and various erythrocyte membrane-associated antigens (namely, glycophorin). Synthesis of milk proteins was not detectable. Only the protein moiety of the glycophorin molecule seemed to be synthesized. The beta2-microglobulin was synthesized in an unbound state as well as bound to a glycoprotein whose relationship with the transplantation or tumor antigens must be determined. The three oncofetal-associated antigens were also synthesized in vitro by human fetal tissues and neoplastic and dysplastic human mammary tissues.
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PMID:Antigens of a human breast carcinoma cell line (BT 20). I. Synthesis of serum proteins, membrane-associated antigens, and oncofetal-associated antigens. 35 46

Apolipoprotein H, also known as beta 2-Glycoprotein I, is a single chain highly glycosylated polypeptide of 326 amino acids. The carbohydrate content of apolipoprotein H is approximately 19% of the molecular weight. Some studies have described the main oligosaccharides forming the glycosylated chains but the carbohydrate inner structures of apolipoprotein H has not been investigated yet. This gap should be filled being glycosylation a very important process which is able to regulate the structure and the biological functions of proteins. Lectins are proteins which specifically bind carbohydrate structures. Affinity chromatography of glycoproteins on immobilized lectins, such as Concanavalin A (Con A), has been proved to be a useful method for oligosaccharide fractionation. N-Linked oligosaccharide structures were shown to interact with Con A according to their branching properties. In the present study, we analyzed the patterns of Con A elution of apolipoprotein H isolated from human plasma. Using Con A affinity chromatography we show that apolipoprotein H has a high degree of heterogeneity in its glycosylated structure. It allowed one to isolate two groups of apolipoprotein H molecules bearing biantennary and truncated hybrids and high mannose and hybrid oligosaccharides. Since Con A affinity chromatography allows fractionation of molecules differing in the extent of carbohydrate branching irrespective of the sialyl residues, we can conclude that mannose residues are masked with other sugars such as galactose-beta (1-4)N-acetylglucosamine, galactose-beta (1-3)N-acetyl-galactosamine and sialic acid linked alpha (2-6) to galactose or to N-acetylgalactosamine, or capped with sulfated residues. Thus, according to our results apolipoprotein H presents truncated hybryd or hybrid-type carbohydrate chains which bear few unmasked mannose residues as terminal sugar. Moreover, isoelectrofocusing of apolipoprotein H forms fractionated on Con A demostrates that weakly bound material presents a predominance of more acidic isoforms than that firmly bound to the lectin, indicating that weakly bound fractions contain molecules which are more negatively charged and that Con A is able to separate glycosylated forms which are not discriminated by isoelectrofocusing.
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PMID:Characterization of the carbohydrate structures of apolipoprotein H through concanavalin A affinity chromatography. 910 19