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)

A hybridoma (3B2-F7) has been established which secretes a monoclonal antibody (Mab) directed against a peptide determinant of human seminal plasma glycoprotein (HSP-gP). The deglycosylation of HSP-gP was performed chemically with TFMS hydrolysis and enzymatically in the presence of detergent and further treated with periodic acid after fixing deglycosylated HSP on plastic wells. The Mab 3B2-F7 (IgM, kappa) exhibited sperm immobilization activity (256 units of SI50) and inhibited sperm binding to human zona pellucida. Human epididymis, pancreatic islets of Langerhan's and distal tubulus of kidney were strongly labelled whilst other tissues were essentially negative by avidin-biotin complex tissue staining with this Mab. The antigen epitope to the Mab was in the 36 kDa molecule of human HSP-gP. The antigenic determinant recognized by Mab 3B2-F7 was destroyed by six different proteases, but was resistant to N-glycanase and other carbohydrate splitting enzymes. This epitope is therefore likely to be composed of a polypeptide chain. Peptide fragments after proteolysis of the HSP molecule with Staph. aureus V8 protease and trypsin retained antigenicity, hence the epitope corresponding to the Mab may be a peptide chain and not dependent on the conformational structure of the polypeptide.
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PMID:Monoclonal antibody recognizing an apparent peptide epitope of human seminal plasma glycoprotein and exhibiting sperm immobilizing activity. 169 87

Human alpha1-acid glycoprotein (hAGP) is a plasma glycoprotein that functions as a major carrier of basic ligands. This is the first report of the recombinant hAGP (rhAGP). In this study, rhAGP was expressed in the methylotropic yeast Pichia pastoris (GS115) using the expression vector, pPIC9, and then purified by anionic exchange, hydrophobic interaction, and gel filtration chromatography. The molecular weight of rhAGP was much lower than that of hAGP, because of the difference in glycan chain content. Results of glycopeptidase F digestion suggest that the peptide moiety of rhAGP was the same as that of hAGP. The results of circular dichroism spectra measurement indicated that rhAGP predominantly formed a beta-sheet-rich structure that was the same as that of hAGP and typical of the lipocalin family. From the experiments using AGP-binding drugs (chlorpromazine, warfarin, and progesterone) and quinaldine red as a probe for the binding site, it was indicated that rhAGP also had the same ligand-binding capacity and binding site structure as hAGP. These findings strongly suggest that this recombinant hAGP (rhAGP) is very useful for the exploration of the ligand-binding site and biological function of hAGP.
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PMID:Construction of expression system for human alpha 1-acid glycoprotein in Pichia pastoris and evaluation of its drug-binding properties. 1522 72

Human C1-inhibitor (C1-Inh) is a serine protease inhibitor and the major regulator of the contact activation pathway as well as the classical and lectin complement pathways. It is known to be a highly glycosylated plasma glycoprotein. However, both the structural features and biological role of C1-Inh glycosylation are largely unknown. Here, we performed for the first time an in-depth site-specific N- and O-glycosylation analysis of C1-Inh combining various mass spectrometric approaches, including C18-porous graphitized carbon (PGC)-LC-ESI-QTOF-MS/MS applying stepping-energy collision-induced dissociation (CID) and electron-transfer dissociation (ETD). Various proteases were applied, partly in combination with PNGase F and exoglycosidase treatment, in order to analyze the (glyco)peptides. The analysis revealed an extensively O-glycosylated N-terminal region. Five novel and five known O-glycosylation sites were identified, carrying mainly core1-type O-glycans. In addition, we detected a heavily O-glycosylated portion spanning from Thr82-Ser121 with up to 16 O-glycans attached. Likewise, all known six N-glycosylation sites were covered and confirmed by this site-specific glycosylation analysis. The glycoforms were in accordance with results on released N-glycans by MALDI-TOF/TOF-MS/MS. The comprehensive characterization of C1-Inh glycosylation described in this study will form the basis for further functional studies on the role of these glycan modifications.
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PMID:N- and O-glycosylation Analysis of Human C1-inhibitor Reveals Extensive Mucin-type O-Glycosylation. 2923 11