PubMed:10608887 JSONTXT

{"project":"ggdb-test","denotations":[{"id":"T1","span":{"begin":187,"end":192},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"T2","span":{"begin":306,"end":313},"obj":"https://acgg.asia/db/ggdb/info/gg015"},{"id":"T3","span":{"begin":306,"end":311},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"T4","span":{"begin":318,"end":323},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"T5","span":{"begin":340,"end":345},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"T6","span":{"begin":541,"end":546},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"T7","span":{"begin":584,"end":589},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"T8","span":{"begin":677,"end":682},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"T9","span":{"begin":696,"end":701},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"T10","span":{"begin":1179,"end":1184},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"T11","span":{"begin":1243,"end":1248},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"T12","span":{"begin":1436,"end":1441},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"T13","span":{"begin":1530,"end":1535},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"T14","span":{"begin":1599,"end":1604},"obj":"https://acgg.asia/db/ggdb/info/gg014"}],"text":"Heparan sulfate D-glucosaminyl 3-O-sulfotransferase-3A sulfates N-unsubstituted glucosamine residues.\n3-O-Sulfation of glucosamine by heparan sulfate D-glucosaminyl 3-O-sulfotransferase (3-OST-1) is the key modification in anticoagulant heparan sulfate synthesis. However, the heparan sulfates modified by 3-OST-2 and 3-OST-3A, isoforms of 3-OST-1, do not have anticoagulant activity, although these isoforms transfer sulfate to the 3-OH position of glucosamine residues. In this study, we characterize the substrate specificity of purified 3-OST-3A at the tetrasaccharide level. The 3-OST-3A enzyme was purified from Sf9 cells infected with recombinant baculovirus containing 3-OST-3A cDNA. Two 3-OST-3A-modified tetrasaccharides were purified from the 3-O-(35)S-sulfated heparan sulfate that was digested by heparin lyases. These tetrasaccharides were analyzed using nitrous acid and enzymatic degradation combined with matrix-assisted laser desorption/ionization-mass spectrometry. Two novel tetrasaccharides were discovered with proposed structures of DeltaUA2S-GlcNS-IdoUA2S-[(35)S]GlcNH(2)3S and DeltaUA2S-GlcNS-IdoUA2S-[3-(35)S]GlcNH(2)3S6S . The results demonstrate that 3-OST-3A sulfates N-unsubstituted glucosamine residues, and the 3-OST-3A modification sites are probably located in defined oligosaccharide sequences. Our study suggests that oligosaccharides with N-unsubstituted glucosamine are precursors for sulfation by 3-OST-3A. The intriguing linkage between N-unsubstituted glucosamine and the 3-O-sulfation by 3-OST-3A may provide a clue to the potential biological functions of 3-OST-3A-modified heparan sulfate."}

{"project":"GlyCosmos6-Glycan-Motif-Image","denotations":[{"id":"T1","span":{"begin":810,"end":817},"obj":"Glycan_Motif"}],"attributes":[{"id":"A1","pred":"image","subj":"T1","obj":"https://api.glycosmos.org/wurcs2image/0.10.0/png/binary/G54161DR"},{"id":"A2","pred":"image","subj":"T1","obj":"https://api.glycosmos.org/wurcs2image/0.10.0/png/binary/G00021MO"}],"text":"Heparan sulfate D-glucosaminyl 3-O-sulfotransferase-3A sulfates N-unsubstituted glucosamine residues.\n3-O-Sulfation of glucosamine by heparan sulfate D-glucosaminyl 3-O-sulfotransferase (3-OST-1) is the key modification in anticoagulant heparan sulfate synthesis. However, the heparan sulfates modified by 3-OST-2 and 3-OST-3A, isoforms of 3-OST-1, do not have anticoagulant activity, although these isoforms transfer sulfate to the 3-OH position of glucosamine residues. In this study, we characterize the substrate specificity of purified 3-OST-3A at the tetrasaccharide level. The 3-OST-3A enzyme was purified from Sf9 cells infected with recombinant baculovirus containing 3-OST-3A cDNA. Two 3-OST-3A-modified tetrasaccharides were purified from the 3-O-(35)S-sulfated heparan sulfate that was digested by heparin lyases. These tetrasaccharides were analyzed using nitrous acid and enzymatic degradation combined with matrix-assisted laser desorption/ionization-mass spectrometry. Two novel tetrasaccharides were discovered with proposed structures of DeltaUA2S-GlcNS-IdoUA2S-[(35)S]GlcNH(2)3S and DeltaUA2S-GlcNS-IdoUA2S-[3-(35)S]GlcNH(2)3S6S . The results demonstrate that 3-OST-3A sulfates N-unsubstituted glucosamine residues, and the 3-OST-3A modification sites are probably located in defined oligosaccharide sequences. Our study suggests that oligosaccharides with N-unsubstituted glucosamine are precursors for sulfation by 3-OST-3A. The intriguing linkage between N-unsubstituted glucosamine and the 3-O-sulfation by 3-OST-3A may provide a clue to the potential biological functions of 3-OST-3A-modified heparan sulfate."}

{"project":"GGDB-2020","denotations":[{"id":"T1","span":{"begin":187,"end":192},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"T2","span":{"begin":306,"end":313},"obj":"https://acgg.asia/db/ggdb/info/gg015"},{"id":"T3","span":{"begin":306,"end":311},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"T4","span":{"begin":318,"end":323},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"T5","span":{"begin":340,"end":345},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"T6","span":{"begin":541,"end":546},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"T7","span":{"begin":584,"end":589},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"T8","span":{"begin":677,"end":682},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"T9","span":{"begin":696,"end":701},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"T10","span":{"begin":1179,"end":1184},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"T11","span":{"begin":1243,"end":1248},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"T12","span":{"begin":1436,"end":1441},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"T13","span":{"begin":1530,"end":1535},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"T14","span":{"begin":1599,"end":1604},"obj":"https://acgg.asia/db/ggdb/info/gg014"}],"text":"Heparan sulfate D-glucosaminyl 3-O-sulfotransferase-3A sulfates N-unsubstituted glucosamine residues.\n3-O-Sulfation of glucosamine by heparan sulfate D-glucosaminyl 3-O-sulfotransferase (3-OST-1) is the key modification in anticoagulant heparan sulfate synthesis. However, the heparan sulfates modified by 3-OST-2 and 3-OST-3A, isoforms of 3-OST-1, do not have anticoagulant activity, although these isoforms transfer sulfate to the 3-OH position of glucosamine residues. In this study, we characterize the substrate specificity of purified 3-OST-3A at the tetrasaccharide level. The 3-OST-3A enzyme was purified from Sf9 cells infected with recombinant baculovirus containing 3-OST-3A cDNA. Two 3-OST-3A-modified tetrasaccharides were purified from the 3-O-(35)S-sulfated heparan sulfate that was digested by heparin lyases. These tetrasaccharides were analyzed using nitrous acid and enzymatic degradation combined with matrix-assisted laser desorption/ionization-mass spectrometry. Two novel tetrasaccharides were discovered with proposed structures of DeltaUA2S-GlcNS-IdoUA2S-[(35)S]GlcNH(2)3S and DeltaUA2S-GlcNS-IdoUA2S-[3-(35)S]GlcNH(2)3S6S . The results demonstrate that 3-OST-3A sulfates N-unsubstituted glucosamine residues, and the 3-OST-3A modification sites are probably located in defined oligosaccharide sequences. Our study suggests that oligosaccharides with N-unsubstituted glucosamine are precursors for sulfation by 3-OST-3A. The intriguing linkage between N-unsubstituted glucosamine and the 3-O-sulfation by 3-OST-3A may provide a clue to the potential biological functions of 3-OST-3A-modified heparan sulfate."}

{"project":"sentences","denotations":[{"id":"T1","span":{"begin":0,"end":101},"obj":"Sentence"},{"id":"T2","span":{"begin":102,"end":263},"obj":"Sentence"},{"id":"T3","span":{"begin":264,"end":471},"obj":"Sentence"},{"id":"T4","span":{"begin":472,"end":579},"obj":"Sentence"},{"id":"T5","span":{"begin":580,"end":691},"obj":"Sentence"},{"id":"T6","span":{"begin":692,"end":825},"obj":"Sentence"},{"id":"T7","span":{"begin":826,"end":984},"obj":"Sentence"},{"id":"T8","span":{"begin":985,"end":1149},"obj":"Sentence"},{"id":"T9","span":{"begin":1150,"end":1329},"obj":"Sentence"},{"id":"T10","span":{"begin":1330,"end":1445},"obj":"Sentence"},{"id":"T11","span":{"begin":1446,"end":1633},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"text":"Heparan sulfate D-glucosaminyl 3-O-sulfotransferase-3A sulfates N-unsubstituted glucosamine residues.\n3-O-Sulfation of glucosamine by heparan sulfate D-glucosaminyl 3-O-sulfotransferase (3-OST-1) is the key modification in anticoagulant heparan sulfate synthesis. However, the heparan sulfates modified by 3-OST-2 and 3-OST-3A, isoforms of 3-OST-1, do not have anticoagulant activity, although these isoforms transfer sulfate to the 3-OH position of glucosamine residues. In this study, we characterize the substrate specificity of purified 3-OST-3A at the tetrasaccharide level. The 3-OST-3A enzyme was purified from Sf9 cells infected with recombinant baculovirus containing 3-OST-3A cDNA. Two 3-OST-3A-modified tetrasaccharides were purified from the 3-O-(35)S-sulfated heparan sulfate that was digested by heparin lyases. These tetrasaccharides were analyzed using nitrous acid and enzymatic degradation combined with matrix-assisted laser desorption/ionization-mass spectrometry. Two novel tetrasaccharides were discovered with proposed structures of DeltaUA2S-GlcNS-IdoUA2S-[(35)S]GlcNH(2)3S and DeltaUA2S-GlcNS-IdoUA2S-[3-(35)S]GlcNH(2)3S6S . The results demonstrate that 3-OST-3A sulfates N-unsubstituted glucosamine residues, and the 3-OST-3A modification sites are probably located in defined oligosaccharide sequences. Our study suggests that oligosaccharides with N-unsubstituted glucosamine are precursors for sulfation by 3-OST-3A. The intriguing linkage between N-unsubstituted glucosamine and the 3-O-sulfation by 3-OST-3A may provide a clue to the potential biological functions of 3-OST-3A-modified heparan sulfate."}

{"project":"GlyCosmos6-Glycan-Motif-Structure","denotations":[{"id":"T1","span":{"begin":810,"end":817},"obj":"https://glytoucan.org/Structures/Glycans/G00021MO"},{"id":"T2","span":{"begin":810,"end":817},"obj":"https://glytoucan.org/Structures/Glycans/G54161DR"}],"text":"Heparan sulfate D-glucosaminyl 3-O-sulfotransferase-3A sulfates N-unsubstituted glucosamine residues.\n3-O-Sulfation of glucosamine by heparan sulfate D-glucosaminyl 3-O-sulfotransferase (3-OST-1) is the key modification in anticoagulant heparan sulfate synthesis. However, the heparan sulfates modified by 3-OST-2 and 3-OST-3A, isoforms of 3-OST-1, do not have anticoagulant activity, although these isoforms transfer sulfate to the 3-OH position of glucosamine residues. In this study, we characterize the substrate specificity of purified 3-OST-3A at the tetrasaccharide level. The 3-OST-3A enzyme was purified from Sf9 cells infected with recombinant baculovirus containing 3-OST-3A cDNA. Two 3-OST-3A-modified tetrasaccharides were purified from the 3-O-(35)S-sulfated heparan sulfate that was digested by heparin lyases. These tetrasaccharides were analyzed using nitrous acid and enzymatic degradation combined with matrix-assisted laser desorption/ionization-mass spectrometry. Two novel tetrasaccharides were discovered with proposed structures of DeltaUA2S-GlcNS-IdoUA2S-[(35)S]GlcNH(2)3S and DeltaUA2S-GlcNS-IdoUA2S-[3-(35)S]GlcNH(2)3S6S . The results demonstrate that 3-OST-3A sulfates N-unsubstituted glucosamine residues, and the 3-OST-3A modification sites are probably located in defined oligosaccharide sequences. Our study suggests that oligosaccharides with N-unsubstituted glucosamine are precursors for sulfation by 3-OST-3A. The intriguing linkage between N-unsubstituted glucosamine and the 3-O-sulfation by 3-OST-3A may provide a clue to the potential biological functions of 3-OST-3A-modified heparan sulfate."}

{"project":"Glycosmos6-GlycoEpitope","denotations":[{"id":"T1","span":{"begin":0,"end":15},"obj":"http://www.glycoepitope.jp/epitopes/EP0086"},{"id":"T2","span":{"begin":134,"end":149},"obj":"http://www.glycoepitope.jp/epitopes/EP0086"},{"id":"T3","span":{"begin":237,"end":252},"obj":"http://www.glycoepitope.jp/epitopes/EP0086"},{"id":"T4","span":{"begin":773,"end":788},"obj":"http://www.glycoepitope.jp/epitopes/EP0086"},{"id":"T5","span":{"begin":1617,"end":1632},"obj":"http://www.glycoepitope.jp/epitopes/EP0086"}],"text":"Heparan sulfate D-glucosaminyl 3-O-sulfotransferase-3A sulfates N-unsubstituted glucosamine residues.\n3-O-Sulfation of glucosamine by heparan sulfate D-glucosaminyl 3-O-sulfotransferase (3-OST-1) is the key modification in anticoagulant heparan sulfate synthesis. However, the heparan sulfates modified by 3-OST-2 and 3-OST-3A, isoforms of 3-OST-1, do not have anticoagulant activity, although these isoforms transfer sulfate to the 3-OH position of glucosamine residues. In this study, we characterize the substrate specificity of purified 3-OST-3A at the tetrasaccharide level. The 3-OST-3A enzyme was purified from Sf9 cells infected with recombinant baculovirus containing 3-OST-3A cDNA. Two 3-OST-3A-modified tetrasaccharides were purified from the 3-O-(35)S-sulfated heparan sulfate that was digested by heparin lyases. These tetrasaccharides were analyzed using nitrous acid and enzymatic degradation combined with matrix-assisted laser desorption/ionization-mass spectrometry. Two novel tetrasaccharides were discovered with proposed structures of DeltaUA2S-GlcNS-IdoUA2S-[(35)S]GlcNH(2)3S and DeltaUA2S-GlcNS-IdoUA2S-[3-(35)S]GlcNH(2)3S6S . The results demonstrate that 3-OST-3A sulfates N-unsubstituted glucosamine residues, and the 3-OST-3A modification sites are probably located in defined oligosaccharide sequences. Our study suggests that oligosaccharides with N-unsubstituted glucosamine are precursors for sulfation by 3-OST-3A. The intriguing linkage between N-unsubstituted glucosamine and the 3-O-sulfation by 3-OST-3A may provide a clue to the potential biological functions of 3-OST-3A-modified heparan sulfate."}

{"project":"bionlp-st-pc-2013-training","denotations":[{"id":"T1","span":{"begin":0,"end":54},"obj":"Gene_or_gene_product"},{"id":"T2","span":{"begin":80,"end":91},"obj":"Simple_chemical"},{"id":"T3","span":{"begin":119,"end":130},"obj":"Simple_chemical"},{"id":"T4","span":{"begin":134,"end":185},"obj":"Gene_or_gene_product"},{"id":"T5","span":{"begin":187,"end":194},"obj":"Gene_or_gene_product"},{"id":"T6","span":{"begin":237,"end":252},"obj":"Simple_chemical"},{"id":"T7","span":{"begin":277,"end":293},"obj":"Simple_chemical"},{"id":"T8","span":{"begin":306,"end":313},"obj":"Gene_or_gene_product"},{"id":"T9","span":{"begin":318,"end":326},"obj":"Gene_or_gene_product"},{"id":"T10","span":{"begin":340,"end":347},"obj":"Gene_or_gene_product"},{"id":"T11","span":{"begin":418,"end":425},"obj":"Simple_chemical"},{"id":"T12","span":{"begin":433,"end":437},"obj":"Simple_chemical"},{"id":"T13","span":{"begin":450,"end":461},"obj":"Simple_chemical"},{"id":"T14","span":{"begin":541,"end":549},"obj":"Gene_or_gene_product"},{"id":"T15","span":{"begin":557,"end":572},"obj":"Simple_chemical"},{"id":"T16","span":{"begin":584,"end":592},"obj":"Gene_or_gene_product"},{"id":"T17","span":{"begin":677,"end":685},"obj":"Gene_or_gene_product"},{"id":"T18","span":{"begin":696,"end":704},"obj":"Gene_or_gene_product"},{"id":"T19","span":{"begin":714,"end":730},"obj":"Simple_chemical"},{"id":"T20","span":{"begin":773,"end":788},"obj":"Simple_chemical"},{"id":"T21","span":{"begin":810,"end":824},"obj":"Gene_or_gene_product"},{"id":"T22","span":{"begin":832,"end":848},"obj":"Simple_chemical"},{"id":"T23","span":{"begin":869,"end":881},"obj":"Simple_chemical"},{"id":"T24","span":{"begin":995,"end":1011},"obj":"Simple_chemical"},{"id":"T25","span":{"begin":1056,"end":1097},"obj":"Simple_chemical"},{"id":"T26","span":{"begin":1102,"end":1147},"obj":"Simple_chemical"},{"id":"T27","span":{"begin":1179,"end":1187},"obj":"Gene_or_gene_product"},{"id":"T28","span":{"begin":1213,"end":1224},"obj":"Simple_chemical"},{"id":"T29","span":{"begin":1243,"end":1251},"obj":"Gene_or_gene_product"},{"id":"T30","span":{"begin":1303,"end":1318},"obj":"Simple_chemical"},{"id":"T31","span":{"begin":1354,"end":1370},"obj":"Simple_chemical"},{"id":"T32","span":{"begin":1392,"end":1403},"obj":"Simple_chemical"},{"id":"T33","span":{"begin":1436,"end":1444},"obj":"Gene_or_gene_product"},{"id":"T34","span":{"begin":1493,"end":1504},"obj":"Simple_chemical"},{"id":"T35","span":{"begin":1530,"end":1538},"obj":"Gene_or_gene_product"},{"id":"T36","span":{"begin":1599,"end":1607},"obj":"Gene_or_gene_product"},{"id":"T37","span":{"begin":1617,"end":1632},"obj":"Simple_chemical"}],"text":"Heparan sulfate D-glucosaminyl 3-O-sulfotransferase-3A sulfates N-unsubstituted glucosamine residues.\n3-O-Sulfation of glucosamine by heparan sulfate D-glucosaminyl 3-O-sulfotransferase (3-OST-1) is the key modification in anticoagulant heparan sulfate synthesis. However, the heparan sulfates modified by 3-OST-2 and 3-OST-3A, isoforms of 3-OST-1, do not have anticoagulant activity, although these isoforms transfer sulfate to the 3-OH position of glucosamine residues. In this study, we characterize the substrate specificity of purified 3-OST-3A at the tetrasaccharide level. The 3-OST-3A enzyme was purified from Sf9 cells infected with recombinant baculovirus containing 3-OST-3A cDNA. Two 3-OST-3A-modified tetrasaccharides were purified from the 3-O-(35)S-sulfated heparan sulfate that was digested by heparin lyases. These tetrasaccharides were analyzed using nitrous acid and enzymatic degradation combined with matrix-assisted laser desorption/ionization-mass spectrometry. Two novel tetrasaccharides were discovered with proposed structures of DeltaUA2S-GlcNS-IdoUA2S-[(35)S]GlcNH(2)3S and DeltaUA2S-GlcNS-IdoUA2S-[3-(35)S]GlcNH(2)3S6S . The results demonstrate that 3-OST-3A sulfates N-unsubstituted glucosamine residues, and the 3-OST-3A modification sites are probably located in defined oligosaccharide sequences. Our study suggests that oligosaccharides with N-unsubstituted glucosamine are precursors for sulfation by 3-OST-3A. The intriguing linkage between N-unsubstituted glucosamine and the 3-O-sulfation by 3-OST-3A may provide a clue to the potential biological functions of 3-OST-3A-modified heparan sulfate."}

{"project":"glycogenes","denotations":[{"id":"PD-GlycoGenes20190927-B_T1","span":{"begin":187,"end":192},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"PD-GlycoGenes20190927-B_T2","span":{"begin":306,"end":313},"obj":"https://acgg.asia/db/ggdb/info/gg015"},{"id":"PD-GlycoGenes20190927-B_T3","span":{"begin":306,"end":311},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"PD-GlycoGenes20190927-B_T4","span":{"begin":318,"end":323},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"PD-GlycoGenes20190927-B_T5","span":{"begin":340,"end":345},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"PD-GlycoGenes20190927-B_T6","span":{"begin":541,"end":546},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"PD-GlycoGenes20190927-B_T7","span":{"begin":584,"end":589},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"PD-GlycoGenes20190927-B_T8","span":{"begin":677,"end":682},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"PD-GlycoGenes20190927-B_T9","span":{"begin":696,"end":701},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"PD-GlycoGenes20190927-B_T10","span":{"begin":1179,"end":1184},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"PD-GlycoGenes20190927-B_T11","span":{"begin":1243,"end":1248},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"PD-GlycoGenes20190927-B_T12","span":{"begin":1436,"end":1441},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"PD-GlycoGenes20190927-B_T13","span":{"begin":1530,"end":1535},"obj":"https://acgg.asia/db/ggdb/info/gg014"},{"id":"PD-GlycoGenes20190927-B_T14","span":{"begin":1599,"end":1604},"obj":"https://acgg.asia/db/ggdb/info/gg014"}],"text":"Heparan sulfate D-glucosaminyl 3-O-sulfotransferase-3A sulfates N-unsubstituted glucosamine residues.\n3-O-Sulfation of glucosamine by heparan sulfate D-glucosaminyl 3-O-sulfotransferase (3-OST-1) is the key modification in anticoagulant heparan sulfate synthesis. However, the heparan sulfates modified by 3-OST-2 and 3-OST-3A, isoforms of 3-OST-1, do not have anticoagulant activity, although these isoforms transfer sulfate to the 3-OH position of glucosamine residues. In this study, we characterize the substrate specificity of purified 3-OST-3A at the tetrasaccharide level. The 3-OST-3A enzyme was purified from Sf9 cells infected with recombinant baculovirus containing 3-OST-3A cDNA. Two 3-OST-3A-modified tetrasaccharides were purified from the 3-O-(35)S-sulfated heparan sulfate that was digested by heparin lyases. These tetrasaccharides were analyzed using nitrous acid and enzymatic degradation combined with matrix-assisted laser desorption/ionization-mass spectrometry. Two novel tetrasaccharides were discovered with proposed structures of DeltaUA2S-GlcNS-IdoUA2S-[(35)S]GlcNH(2)3S and DeltaUA2S-GlcNS-IdoUA2S-[3-(35)S]GlcNH(2)3S6S . The results demonstrate that 3-OST-3A sulfates N-unsubstituted glucosamine residues, and the 3-OST-3A modification sites are probably located in defined oligosaccharide sequences. Our study suggests that oligosaccharides with N-unsubstituted glucosamine are precursors for sulfation by 3-OST-3A. The intriguing linkage between N-unsubstituted glucosamine and the 3-O-sulfation by 3-OST-3A may provide a clue to the potential biological functions of 3-OST-3A-modified heparan sulfate."}