Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:Q7LGC8 (HSD)
 3,196 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 3'-phosphoadenylylsulfate:chondroitin sulfotransferase (EC 2.8.2.5) was purified to homogeneity (about 760-fold) from the cytosolic fraction of calf arterial tissue by Con A-Sepharose, ion exchange and affinity chromatography. The enzyme has a molecular mass of 38000 Da, optimal activity at pH 6.0 (100%) and 7.25 (75%), requires divalent cations for maximal activity (Mn2+ greater than Mg2+, Ca2+) and exhibits specificity towards desulfated chondroitin sulfate and oligosaccharides derived therefrom. The enzyme transfers sulfate groups from [35S]phosphoadenylylsulfate exclusively to C-6 OH groups of N-acetylgalactosamine units of the acceptor substrates. Maximal sulfate transfer occurs at 2mM chondroitin disaccharide units (100%), the transfer rates decreasing with decreasing chain length in the order deca (55%), octa (17%) and hexasaccharides (4%). Lineweaver-Burk plots revealed equal maximal velocities for chondroitin, deca-, octa- and hexasaccharide, but decreasing Km values. Chondroitin 4-sulfate has 21% of the acceptor potency exhibited by chondroitin, whereas dermatan sulfate, heparan sulfate and hyaluronate and the chondroitin tetrasaccharide showed no acceptor properties. Analysis of the reaction products formed by prolonged enzymatic sulfation of a reduced chondroitin hexasaccharide [GlcA-GalNAc]2-GlcA-GalNAc-ol revealed that the preterminal N-acetylgalactosamine from the non-reducing end and the internal N-acetylgalactosamine but not the N-acetylgalactosaminitol were sulfated and that no hexasaccharide disulfate was formed by the action of chondroitin 6-sulfotransferase. Chondroitin 6-sulfotransferase is considered to possess a binding region capable of accommodating a nonsulfated oligosaccharide sequence of at least six sugars and is believed to act in the course of chondroitin sulfate synthesis in cooperation with, but shortly after, the enzymes involved in the chain elongation reaction.
 ...
PMID:Purification and characterization of a 3'-phosphoadenylylsulfate:chondroitin 6-sulfotransferase from arterial tissue. 345 54

Chondroitin 6-sulfotransferase (C6ST) catalyzes the transfer of sulfate from 3'-phosphoadenosine 5'-phosphosulfate to position 6 of the N-acetylgalactosamine residue of chondroitin. The enzyme has been purified previously to apparent homogeneity from the serum-free culture medium of chick chondrocytes. The purified enzyme also catalyzed the sulfation of keratan sulfate. We have now cloned the cDNA of the enzyme. This cDNA contains a single open reading frame that predicts a protein composed of 458 amino acid residues. The protein predicts a Type II transmembrane topology similar to other glycosyltransferases and heparin/heparan sulfate N-sulfotransferase/N-deacetylases. Evidence that the predicted protein corresponds to the previously purified C6ST was the following: (a) the predicted sequence of the protein contains all of the known amino acid sequence, (b) when the cDNA was introduced in a eukaryotic expression vector and transfected in COS-7 cells, both the C6ST activity and the keratan sulfate sulfotransferase activity were overexpressed, (c) a polyclonal antibody raised against a fusion peptide, which was expressed from a cDNA containing the sequence coding for 150 amino acid residues of the predicted protein, cross-reacted to the purified C6ST, and (d) the predicted protein contained six potential sites for N-glycosylation, which corresponds to the observation that the purified C6ST is an N-linked glycoprotein. The amino-terminal amino acid sequence of the purified protein was found in the transmembrane domain, suggesting that the purified protein might be released from the chondrocytes after proteolytic cleavage in the transmembrane domain.
 ...
PMID:Molecular cloning and expression of chick chondrocyte chondroitin 6-sulfotransferase. 762 89

A soluble sulfotransferase that could 6-sulfate both chondroitin sulfate and corneal keratan sulfate was purified 27,500-fold using a sequence of affinity chromatographic steps with heparin-Sepharose, wheat germ agglutinin-agarose, and 3',5'-ADP-agarose. The essentially pure enzyme had a specific activity 40 times greater than the most purified chondroitin 6-sulfotransferase previously reported and exhibited a single sharp Coomassie Blue-stained and a heavy silver-stained protein band of 75 kDa on SDS-polyacrylamide gel electrophoresis. Chromatography of the purified enzyme on Sephacryl demonstrated a size of 150 kDa, which indicated that the native enzyme exists as a dimer. In addition to 6-sulfation of nonsulfated GalNAc, the purified serum enzyme had the ability to sulfate GalNAc 4-sulfate residues to give GalNAc 4,6-disulfate residues. The purified enzyme exhibited a Km of 40 microM for adenosine 3'-phosphate 5'-phosphosulfate when either chondroitin sulfate or corneal keratan sulfate were used as the acceptors. Use of both chondroitin sulfate and keratan sulfate in the same experiment demonstrated mutual competition, establishing that the sulfation of these substrates is by the same enzyme. Photoaffinity labeling of the purified enzyme with 2-azidoadenosine 3',5'-di[5'-32P]phosphate occurred only with the 75-kDa protein, confirming that this is the chondroitin 6-sulfotransferase/keratan sulfotransferase.
 ...
PMID:Purification, photoaffinity labeling, and characterization of a single enzyme for 6-sulfation of both chondroitin sulfate and keratan sulfate. 767 38

Chondroitin 6-sulfotransferase, which transfers sulfate from 3'-phosphoadenylyl sulfate to position 6 of N-acetylgalactosamine in chondroitin, was purified 1,430-fold to apparent homogeneity with a 22% yield from the serum-free culture medium of chick embryo chondrocytes by affinity chromatography on heparin-Sepharose CL-6B, wheat germ agglutinin-agarose, and 3',5'-ADP-agarose. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified enzyme showed a single broad protein band with an apparent molecular weight of 75,000. Since the purified enzyme has an apparent molecular weight of 160,000 as judged by gel chromatography on Superose 12, the active form of chondroitin 6-sulfotransferase may be a dimer. The purified enzyme transferred sulfate to chondroitin, chondroitin sulfate, and corneal keratan sulfate. Chondroitin sulfate E from squid cartilage, dermatan, sulfate, and heparan sulfate hardly served as acceptors of the sulfotransferase. The sulfated product derived from keratan sulfate was degraded by keratanase but not by chondroitinase ABC.
 ...
PMID:Purification of chondroitin 6-sulfotransferase secreted from cultured chick embryo chondrocytes. 840 53

We have previously found that the purified chondroitin 6-sulfotransferase (C6ST), which transfers sulfate from 3'-phosphoadenosine 5'-phosphosulfate (PAPS) to position 6 of N-acetylgalactosamine in chondroitin, catalyzed the sulfation of keratan sulfate, and that both the C6ST activity and the keratan sulfate sulfotransferase (KSST) activity were expressed in COS-7 cells when C6ST cDNA was transfected. In this report we describe some properties of the KSST activity contained in the purified C6ST, and characterize the sulfated products formed from keratan sulfate and partially desulfated keratan sulfate. Optimal pH, requirement for cationic activators, and Km value for PAPS of the KSST activity were very similar to those of the C6ST activity. 35S-Labeled glycosaminoglycans formed from keratan sulfate and partially desulfated keratan sulfate were N-deacetylated by treatment with hydrazine/hydrazine sulfate and then cleaved with HNO2 at pH 4, and the resulting products were reduced with NaB3H4. Analysis of the degradation products with paper chromatography and high performance liquid chromatography provided evidence that C6ST transferred sulfate to position 6 of galactose residue which was glycosidically linked to N-acetylglucosamine 6-sulfate residue or to N-acetylglucosamine residue. Northern blot analysis using poly (A)+ RNA from 12-d-old chick embryos indicated that the message of C6ST was expressed not only in the cartilage but also in the cornea in which keratan sulfate is actively synthesized.
 ...
PMID:Enzymatic sulfation of galactose residue of keratan sulfate by chondroitin 6-sulfotransferase. 899 9

We have previously shown that chondroitin 6-sulfotransferase (C6ST) catalyzes transfer of sulfate not only to position 6 of GalNAc residue of chondroitin but also to position 6 of Gal residue of keratan sulfate. In this study, we examined the sulfation of sialyl lactosamine oligosaccharides by C6ST. C6ST catalyzed transfer of sulfate to NeuAc alpha 2-3Gal beta 1-4GlcNAc (SLN), NeuAc alpha 2-3Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4GlcNAc (SL1L1), NeuAc alpha 2-3Gal beta 1-4(6-sulfo)GlcNAc beta 1-3(6-sulfo)Gal beta 1-4(6-sulfo)GlcNAc (SL2L4), and their desialylated derivatives, but not to NeuAc alpha 2-3Gal beta 1-4(Fuc alpha 1-3)GlcNAc (SLe(x)). The sulfated product formed from SLN was degraded with neuraminidase and reduced with NaBH4. The resulting sulfated disaccharide alditol showed the same retention time in SAX-HPLC as that of [3H]Gal(6SO4) beta 1-4GlcNAc-ol. The sulfated product formed from SLN was also degraded by a reaction sequence of neuraminidase digestion, hydrazinolysis, deamination, and NaBH4 reduction. The final product was coeluted with [3H]Gal(6SO4) beta 1-4anhydromannitol in SAX-HPLC. These observations show that C6ST could transfer sulfate to position 6 of Gal residue of SLN. Incorporation of sulfate into SL2L4 was much higher than the incorporation into SL1L1, suggesting that sulfate moiety attached to adjacent GlcNAc residue may stimulate the transfer of sulfate to Gal residue. The recombinant C6ST also catalyzed sulfation of the sialyl lactosamine oligosaccharides, indicating that a single protein catalyzes sulfation of chondroitin, keratan sulfate, and sialyl lactosamine oligosaccharides. These results raised a possibility that C6ST may be one of the candidates involved in the biosynthesis of sulfated sialyl Lewis x ligand for L-selectin.
 ...
PMID:Sulfation of sialyl lactosamine oligosaccharides by chondroitin 6-sulfotransferase. 914 50

Chondroitin 6-sulfotransferase (C6ST) catalyzes the transfer of sulfate from 3'-phosphoadenosine 5'-phosphosulfate to position 6 of the N-acetylgalactosamine residue of chondroitin. Using chick C6ST cDNA as a probe, we cloned the cDNA of mouse C6ST. The mouse enzyme was predicted to be composed of 472 amino acids, and exhibited 71% sequence identity with the chicken enzyme. The mouse and chicken catalytic domains exposed to the luminal side exhibited 81% identity, while the homology of the remaining regions was less. Transfection and expression of the mouse cDNA in COS-7 cells yielded C6ST activity. Keratan sulfate sulfotransferase activity, which was simultaneously expressed, amounted to 3% of the C6ST activity, this value being significantly lower than that observed in the case of the chicken enzyme. Mouse C6ST mRNA was strongly expressed in the spleen, lung, and eye. In situ hybridization revealed that the transcript was localized in stromal cells in the marginal zone and red pulp of the spleen, and stromal cells in the bone marrow. Fluorescence in situ hybridization analysis revealed the gene is located in mouse chromosome 9.
 ...
PMID:Mouse chondroitin 6-sulfotransferase: molecular cloning, characterization and chromosomal mapping. 959 47

Chondroitin 6-sulfotransferase (C6ST) is the key enzyme in the biosynthesis of chondroitin 6-sulfate, a glycosaminoglycan implicated in chondrogenesis, neoplasia, atherosclerosis, and other processes. C6ST catalyzes the transfer of sulfate from 3'-phosphoadenosine 5'-phosphosulfate to carbon 6 of the N-acetylgalactosamine residues of chondroitin. Based on the previously published avian sequence, we searched the database of expressed sequence tags (dbEST) and obtained partial-length cDNAs that we completed by 5'-RACE using human chondrosarcoma and endothelial-cell RNA as template. Stable transfection of our full-length expression construct into CHO-K1 cells resulted in marked increases in C6ST and keratan sulfate sulfotransferase (KSST) enzymatic activities in cell homogenates. The predicted 411 amino acid sequence of human C6ST contains an N-terminal hydrophobic domain consistent with membrane insertion, four potential sites for N-linked glycosylation, several consensus sequences for protein phosphorylation, and one RGD sequence. The human and chick C6ST cDNA share 51% nucleotide identity, 40% amino acyl identity, and 75% amino acyl conservation. The human C6ST gene structure has been elucidated and exhibits an intron-less coding region, and the gene has been mapped to human chromosome 11 by radiation hybrid panel mapping.
 ...
PMID:Human chondroitin 6-sulfotransferase: cloning, gene structure, and chromosomal localization. 963 83

The cDNA and gene encoding human chondroitin 6-sulfotransferase (C6ST) have been cloned. The expression of a soluble recombinant form of the protein in COS-1 cells produced an active sulfotransferase, which used as acceptor substrates polymer chondroitin, various chondroitin sulfate isoforms and chondroitin sulfate tetrasaccharides. The identification of the reaction products demonstrated that the enzyme transferred sulfate to position 6 of GalNAc in the GlcAbeta1-3GalNAc but not the IdoAalpha1-3GalNAc nor the GlcAbeta1-3GalNAc(4-O-sulfate) sequences. The human C6ST gene spans more than 20 kb and consists of three exons. The protein-coding domain of the C6ST gene is divided into two discrete exons.
 ...
PMID:Functional expression and genomic structure of human chondroitin 6-sulfotransferase. 988 91

A novel human chondroitin 6-O-sulfotransferase, designated C6ST-2, was identified by BLAST analysis of expressed sequence tag using the sequence of a previously described human chondroitin 6-O-sulfotransferase (C6ST-1) as a probe. The new cDNA sequence revealed an open reading frame coding for a protein of 486 amino acids with a type II transmembrane protein topology. The amino acid sequence displayed 24% identity to the human C6ST-1, and the highest sequence identity was found in the COOH-terminal catalytic domain. The expression of a soluble recombinant form of the protein in COS-1 cells produced an active sulfotransferase with marked specificity for polymer chondroitin. In contrast, keratan sulfate and oligosaccharides containing the Galbeta1-4GlcNAc sequence, which are good acceptor substrates for the C6ST-1, hardly served as acceptors. The identification of the reaction product indicated that the enzyme is a novel chondroitin 6-O-sulfotransferase (C6ST-2) that mainly transfers sulfate to N-acetylgalactosamine. The coding region of C6ST-2 was contained in a single exon and localized to chromosome Xp11. Northern blot analysis of human brain poly(A)(+) RNA revealed a single transcript of 2.4 kilobase pairs. Reverse transcription-polymerase chain reaction analysis showed that C6ST-2 is developmentally regulated in various tissues with expression persisting through adulthood in the spleen. Thus, we demonstrated the redundancy in chondroitin 6-O-sulfotransferases capable of forming chondroitin 6-sulfate, which is important for understanding the mechanisms leading to specific changes in the sulfation profile of chondroitin sulfate chains in various tissues during development and malignant transformation.
 ...
PMID:Molecular cloning and expression of a novel chondroitin 6-O-sulfotransferase. 1078 96


1 2 3 Next >>