Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.1.52 (PNGase F)
 1,527 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have identified mature and putative precursor forms of glycophorins expressed in a virus-transformed murine erythroleukaemia (MEL) cell line and compared them with their normal erythroblast counterparts. The following differences were found: (1) the two major MEL cell glycophorins (apparent Mr values 29-30 and 43(x10(3] have greater mobility on polyacrylamide gels than their normal gp-3 and gp-2 counterparts, due at least in part to differences in their oligosaccharide sidechains; (2) MEL cell gp-3 consists of two discrete proteins; and (3) there are more potential glycophorin precursors in MEL cells than in normal mouse erythroblasts. Four proteins, with apparent Mr values of 21, 23, 26 and 27(x10(3], have tentatively been identified as glycophorin precursors, based on the following findings: (1) they are immunologically related to the glycophorins; and (2) their synthesis was induced by dimethyl sulphoxide coincidentally with that of gp-3 and gp-2. They do not appear to be glycoproteins, as evidenced by their lack of incorporation of [3H]galactose, [3H]glucosamine or [3H]mannose. In contrast, gp-3 and gp-2 incorporated [3H]galactose and [3H]glucosamine but not [3H]mannose. Partial characterization of the glycan moieties of MEL cell glycophorins indicates that they consist mostly of tri- and tetrasaccharides, with no indication of any N-linked chains. Hence, the glycans of MEL cell glycophorins are mostly (if not all) O-linked. Furthermore, treatment with N-glycanase did not change their electrophoretic mobility on polyacrylamide gels. MEL cell glycophorins were also shown to be modified by phosphoryl and fatty acyl groups.
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PMID:Glycophorin expression in murine erythroleukaemia cells. 277 19

In this report we examine the primary sequence of a variant glycophorin obtained from erythrocytes of an individual who exhibits an unusual MNSs blood group phenotype. We show that this protein is a hybrid molecule constructed from sequences of alpha- and delta-glycophorins (glycophorins A and B) in a alpha-delta arrangement. Serological typing revealed that the donor's phenotype was M+N+S+s+U+; yet his erythrocytes reacted with some but not all examples of anti-S antisera. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed a variant glycophorin band, and immunoblotting and reaction with N-glycanase suggested that its amino terminus resembled that of M-alpha-glycophorin but that its carboxyl terminus did not. A preparation highly enriched in the variant was obtained and used to generate peptide fragments for sequencing. The sequence revealed that the variant was a hybrid molecule whose amino terminus corresponded to M-alpha-glycophorin and whose carboxyl terminus corresponded to S-delta-glycophorin. CNBr cleavage of the variant glycophorin yielded four peptides. The sequence of the amino-terminal CNBr peptide (residues 1-8) was identical to the amino-terminal octapeptide of M-alpha-glycophorin. The proceeding peptide (residues 9-61) contained a segment identical to residues 9-58 of alpha glycophorin, but its carboxyl-terminal sequence had the Gly-Glu-Met sequence from S-delta-glycophorin (residues 27-29). The other two peptides, insoluble in aqueous solutions, contained highly hydrophobic sequences, identical to residues 30-52 and 53-68 of delta-glycophorin. Sequences of overlapping peptides generated by trypsin and V8 protease confirmed the hybrid nature of the variant glycophorin: residues 1-58 were identical to residues 1-58 of M-alpha-glycophorin, and residues 59-100 were entirely identical to residues 27-68 of S-delta-glycophorin. The variant glycophorin is expected to have 4 additional residues at its carboxyl terminus that correspond to the carboxyl-terminal residues 69-72 of delta-glycophorin. The amino acid sequence arrangement of the variant alpha-delta-glycophorin is an exact reciprocal of that found in another hybrid glycophorin, Sta, that is a delta-alpha hybrid. We propose that the two hybrid glycophorins represent the two possible products resulting from a reciprocal recombination event.
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PMID:Amino acid sequence of an alpha-delta-glycophorin hybrid. A structure reciprocal to Sta delta-alpha-glycophorin hybrid. 279 68

A novel method for the analysis of Ser/Thr-linked sugar chains was made possible by the virtue of unique anthranilic acid (AA, 2-aminobenzoic acid [2AA]) chemistry for labeling carbohydrates in aqueous salt solutions (K. R. Anumula, Anal. Biochem. 350 (2006) 1-23). The protocol for profiling of Ser/Thr carbohydrates by hydrazinolysis was made simple by eliminating intermediary isolation steps involved in a sample preparation such as desalting and various chromatographic purification schemes. A 6-h hydrazinolysis was carried out at 60 degrees C for O-linked oligosaccharides and at 95 degrees C for total oligosaccharides (N-linked with some O-linked). Following evaporation of hydrazine (<10 min), the oligosaccharides were N-acetylated and derivatized with AA in the same reaction mixture containing salts. Presumably, the glycosyl-hydrazines/hydrazones present in the mixture did not interfere with AA labeling. Because AA is the most fluorescent and highly reactive tag for labeling carbohydrates, the procedures described are suitable for the analysis of a limited amount of samples ( approximately 5 microg) by the current high-resolution high-performance liquid chromatography (HPLC) methods. HPLC conditions developed for the separation of O-linked sugar chains based on size on an amide column were satisfactory for quantitative profiling and characterization. Common O-linked sugar chains found in fetuin, equine chorionic gonadotropin, and glycophorin can be analyzed in less than 50 min. In addition, these fast profiling methods were comparable to profiling by PNGase F (peptide N-glycosidase from Flavobacterium meningosepticum) digestion in terms of time, effort, and simplicity and also were highly reproducible for routine testing. The procedures for the release of sugar chains by hydrazinolysis at the microgram level, labeling with fluorescent tag AA, and profiling by HPLC should be useful in characterization of carbohydrates found in glycoproteins.
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PMID:Unique anthranilic acid chemistry facilitates profiling and characterization of Ser/Thr-linked sugar chains following hydrazinolysis. 1795 Jun 86