Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Six glycoforms of plasminogen 2 were isolated using a combination of lectin affinity chromatography and chromatofocussing, and the sialic acid content of each glycoform was determined. The kinetics of activation of each glycoform by tissue-type plasminogen activator were analyzed on a fibrin surface and in solution. The second-order rate constant (measured on a fibrin surface) decreased from 1.65 x 10(6) M-1 s-1 to 3.77 x 10(4) M-1 s-1 as the sialic acid content of the glycoforms increased from 1.3 mol/mol of protein to 13.65 mol/mol of protein. A similar correlation was noted for activation in solution. Each glycoform was converted to plasmin, and the inhibition constants for the reaction between alpha 2-antiplasmin and plasmin glycoforms were determined. All overall Ki values, reflecting the final essentially irreversible complex, were in the picomolar range. Sialic acid does not affect inhibition of plasmin by alpha 2-antiplasmin; however, hypersialylated plasmin does not appear to have a kringle-dependent component to inhibition.
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PMID:Sialic acid content of plasminogen 2 glycoforms as a regulator of fibrinolytic activity. Isolation, carbohydrate analysis, and kinetic characterization of six glycoforms of plasminogen. 789 Jul 18

A recombinant human plasminogen activator hybrid variant K2tu-PA, expressed in Chinese hamster ovary cells, is partially glycosylated at Asn12 (A chain, kringle-2 domain) and completely glycosylated at Asn247 (B chain, protease domain). After release of the N-linked carbohydrate chains by peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F, the oligosaccharides were separated from the protein by gel permeation chromatography, then fractionated by FPLC on Mono Q, followed by HPLC on Lichrosorb-NH2, and analysed by 500-MHz 1H-NMR spectroscopy. The following types of carbohydrates occur: monosialylated diantennary (8%), disialylated diantennary (45%), disialylated tri- and tri'-antennary (1%), trisialylated tri- and tri'-antennary (28%), and tetrasialylated tetra-antennary (18%) structures, all having fucose in alpha(1-6)-linkage at the Asn-bound N-acetylglucosamine. Sialic acid occurred exclusively in alpha(2-3)-linkage to galactose, and consisted of N-acetylneuraminic acid (94%), N-glycolylneuraminic acid (3%), and N-acetyl-9-O-acetylneuraminic acid (3%). In addition, glycopeptide fragments corresponding with the A or B chain of K2tu-PA were analysed. The oligosaccharides attached to Asn12 are less processed than those attached to Asn247. Comparison of the glycosylation pattern of K2tu-PA with that of tissue-type plasminogen activator from different biological sources showed significant differences. Profiling studies on different K2tu-PA production batches demonstrated that the structures of N-linked oligosaccharides were identical, but that relative amounts vary with the applied isolation procedure of the chimeric glycoprotein.
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PMID:Primary structure of N-linked carbohydrate chains of a human chimeric plasminogen activator K2tu-PA expressed in Chinese hamster ovary cells. 846 41

The recombinant plasminogen activator (rDSPA alpha 1) from the vampire bat Desmodus rotundus is a promising new thrombolytic agent that exhibits a superior pharmacological profile if compared to tissue-type plasminogen activator (t-PA) or streptokinase. In the present study the structures of the carbohydrate moieties at the two N-glycosylation sites (Asn-117, Asn-362) of rDSPA alpha 1 expressed in Chinese hamster ovary cells were determined. N-Linked glycans were enzymatically released from isolated tryptic glycopeptides by peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F digestion and separated by two-dimensional HPLC. Oligosaccharide structures were characterized by analysis of carbohydrate composition and linkage, by mass spectrometry, and by sequence analysis in which the fluorescently labeled glycans were cleaved with an array of specific exoglycosidases. More than 30 different oligosaccharides were identified. The results revealed that Asn-117 carried a mixture of one high-mannose structure (17% of site-specific glycosylation), three hybrid glycans (26%) and predominantly biantennary complex N-glycans (54%). Glycosylation site Asn-362 was found to comprise complex glycans with biantennary (50%), 2,4- and 2,6-branched triantennary (21%, 11%), and tetraantennary structures (10%), which were fucosylated at the innermost residue of N-acetylglucosamine. Mainly neutral and monosialylated glycans, and smaller quantities of disialylated glycans, were detected at both glycosylation sites. Sialic acid was alpha 2-3 linked to galactose exclusively. As shown in this study the N-glycans attached to Asn-117 of rDSPA alpha 1 are more processed during biosynthesis than the high-mannose structures linked to Asn-117 of t-PA, to which the polypeptide backbone of rDSPA alpha 1 is structurally closely related.
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PMID:Analysis of site-specific N-glycosylation of recombinant Desmodus rotundus salivary plasminogen activator rDSPA alpha 1 expressed in Chinese hamster ovary cells. 906 66