Enzymes
| UniProtKB help_outline | 3,773 proteins |
| Enzyme class help_outline |
|
| GO Molecular Function help_outline |
|
Reaction participants Show >> << Hide
-
Namehelp_outline
N4-(α-D-Man-(1→3)-[α-D-Man-(1→3)-[α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc)-L-asparaginyl-[protein] (N-glucan mannose isomer 5A1,2)
Identifier
RHEA-COMP:14367
Reactive part
help_outline
- Name help_outline N4-(α-D-Man-(1→3)-[α-D-Man-(1→3)-[α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc)-L-Asn residue Identifier CHEBI:59087 Charge 0 Formula C50H82N4O37 SMILEShelp_outline [C@@H]1([C@H]([C@H]([C@@H]([C@H](O1)CO[C@@H]2[C@H]([C@H]([C@@H]([C@H](O2)CO[C@@H]3[C@H]([C@H]([C@@H]([C@H](O3)CO)O)O)O)O)O[C@@H]4[C@H]([C@H]([C@@H]([C@H](O4)CO)O)O)O)O)O)O[C@@H]5[C@H]([C@H]([C@@H]([C@H](O5)CO)O)O)O)O)O[C@H]6[C@@H]([C@H]([C@@H](O[C@@H]6CO)O[C@H]7[C@@H]([C@H]([C@@H](O[C@@H]7CO)NC(C[C@@H](C(=O)*)N*)=O)NC(=O)C)O)NC(=O)C)O 2D coordinates Mol file for the small molecule Search links Involved in 5 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline UDP-N-acetyl-α-D-glucosamine Identifier CHEBI:57705 (Beilstein: 4286654) help_outline Charge -2 Formula C17H25N3O17P2 InChIKeyhelp_outline LFTYTUAZOPRMMI-CFRASDGPSA-L SMILEShelp_outline CC(=O)N[C@@H]1[C@@H](O)[C@H](O)[C@@H](CO)O[C@@H]1OP([O-])(=O)OP([O-])(=O)OC[C@H]1O[C@H]([C@H](O)[C@@H]1O)n1ccc(=O)[nH]c1=O 2D coordinates Mol file for the small molecule Search links Involved in 88 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
-
Namehelp_outline
N4-{β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→3)-[α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc}-L-asparaginyl-[protein]
Identifier
RHEA-COMP:14368
Reactive part
help_outline
- Name help_outline N4-{β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→3)-[α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc}-L-Asn residue Identifier CHEBI:60625 Charge 0 Formula C58H95N5O42 SMILEShelp_outline [C@@H]1([C@@H]([C@H]([C@@H]([C@H](O1)CO)O)O)NC(=O)C)O[C@@H]2[C@H](O[C@@H]([C@H]([C@@H]2O)O)CO)O[C@@H]3[C@@H]([C@@H](O[C@@H]([C@H]3O)CO[C@@H]4[C@H]([C@H]([C@@H]([C@H](O4)CO[C@@H]5[C@H]([C@H]([C@@H]([C@H](O5)CO)O)O)O)O)O[C@@H]6[C@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O)O)O[C@H]7[C@@H]([C@H]([C@@H](O[C@@H]7CO)O[C@H]8[C@@H]([C@H]([C@@H](O[C@@H]8CO)NC(C[C@@H](C(=O)*)N*)=O)NC(=O)C)O)NC(=O)C)O)O 2D coordinates Mol file for the small molecule Search links Involved in 2 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline UDP Identifier CHEBI:58223 Charge -3 Formula C9H11N2O12P2 InChIKeyhelp_outline XCCTYIAWTASOJW-XVFCMESISA-K SMILEShelp_outline O[C@@H]1[C@@H](COP([O-])(=O)OP([O-])([O-])=O)O[C@H]([C@@H]1O)n1ccc(=O)[nH]c1=O 2D coordinates Mol file for the small molecule Search links Involved in 611 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,717 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:11456 | RHEA:11457 | RHEA:11458 | RHEA:11459 | |
|---|---|---|---|---|
| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
| UniProtKB help_outline |
|
|||
| EC numbers help_outline | ||||
| Gene Ontology help_outline | ||||
| KEGG help_outline | ||||
| MetaCyc help_outline |
Publications
-
Molecular basis of N-acetylglucosaminyltransferase I deficiency in Arabidopsis thaliana plants lacking complex N-glycans.
Strasser R., Stadlmann J., Svoboda B., Altmann F., Gloessl J., Mach L.
GnTI (N-acetylglucosaminyltransferase I) is a Golgi-resident enzyme essential for the processing of high-mannose to hybrid and complex N-glycans. The Arabidopsis thaliana cgl mutant lacks GnTI activity and as a consequence accumulates oligomannosidic structures. Molecular cloning of cgl GnTI cDNA ... >> More
GnTI (N-acetylglucosaminyltransferase I) is a Golgi-resident enzyme essential for the processing of high-mannose to hybrid and complex N-glycans. The Arabidopsis thaliana cgl mutant lacks GnTI activity and as a consequence accumulates oligomannosidic structures. Molecular cloning of cgl GnTI cDNA revealed a point mutation, which causes a critical amino acid substitution (Asp144-->Asn), thereby creating an additional N-glycosylation site. Heterologous expression of cgl GnTI in insect cells confirmed its lack of activity and the use of the N-glycosylation site. Remarkably, introduction of the Asp144-->Asn mutation into rabbit GnTI, which does not result in the formation of a new N-glycosylation site, led to a protein with strongly reduced, but still detectable enzymic activity. Expression of Asn144 rabbit GnTI in cgl plants could partially restore complex N-glycan formation. These results indicate that the complete deficiency of GnTI activity in cgl plants is mainly due to the additional N-glycan, which appears to interfere with the proper folding of the enzyme. << Less
-
Control of glycoprotein synthesis. Bovine colostrum UDP-N-acetylglucosamine:alpha-D-mannoside beta 2-N-acetylglucosaminyltransferase I. Separation from UDP-N-acetylglucosamine:alpha-D-mannoside beta 2-N-acetylglucosaminyltransferase II, partial purification, and substrate specificity.
Harpaz N., Schachter H.
J Biol Chem 255:4885-4893(1980) [PubMed] [EuropePMC]
This publication is cited by 1 other entry.
-
X-ray crystal structure of rabbit N-acetylglucosaminyltransferase I: catalytic mechanism and a new protein superfamily.
Unligil U.M., Zhou S., Yuwaraj S., Sarkar M., Schachter H., Rini J.M.
N:-acetylglucosaminyltransferase I (GnT I) serves as the gateway from oligomannose to hybrid and complex N:-glycans and plays a critical role in mammalian development and possibly all metazoans. We have determined the X-ray crystal structure of the catalytic fragment of GnT I in the absence and pr ... >> More
N:-acetylglucosaminyltransferase I (GnT I) serves as the gateway from oligomannose to hybrid and complex N:-glycans and plays a critical role in mammalian development and possibly all metazoans. We have determined the X-ray crystal structure of the catalytic fragment of GnT I in the absence and presence of bound UDP-GlcNAc/Mn(2+) at 1.5 and 1.8 A resolution, respectively. The structures identify residues critical for substrate binding and catalysis and provide evidence for similarity, at the mechanistic level, to the deglycosylation step of retaining beta-glycosidases. The structuring of a 13 residue loop, resulting from UDP-GlcNAc/Mn(2+) binding, provides an explanation for the ordered sequential 'Bi Bi' kinetics shown by GnT I. Analysis reveals a domain shared with Bacillus subtilis glycosyltransferase SpsA, bovine beta-1,4-galactosyl transferase 1 and Escherichia coli N:-acetylglucosamine-1-phosphate uridyltransferase. The low sequence identity, conserved fold and related functional features shown by this domain define a superfamily whose members probably share a common ancestor. Sequence analysis and protein threading show that the domain is represented in proteins from several glycosyltransferase families. << Less
-
Studies on UDP-N-acetylglucosamine : alpha-mannoside beta-N-acetylglucosaminyltransferase of rat liver and hepatomas.
Miyagi T., Tsuiki S.
When homogenates of rat liver and hepatomas were centrifuged at 78 000 X g, over 90% of liver N-acetylglucosaminyltransferase assayed with beta-galactosidase- and beta-N-acetylhexosaminidase-treated asialofetuin as acceptor was recovered in the particulate fraction, while as much as 24% of hepatom ... >> More
When homogenates of rat liver and hepatomas were centrifuged at 78 000 X g, over 90% of liver N-acetylglucosaminyltransferase assayed with beta-galactosidase- and beta-N-acetylhexosaminidase-treated asialofetuin as acceptor was recovered in the particulate fraction, while as much as 24% of hepatoma transferase was in the supernatant fraction. The particulate transferase solubilized by 0.2% sodium deoxycholate emerged from a DEAE-cellulose column at 0.04 M NaCl (transferase A). The supernatant fractions from all the hepatomas tested contained a second N-acetylglucosaminyltransferase eluted from the column at 0.02 M NaCl (transferase B). Transferase B was absent from liver supernatant fraction. The activities of these transferases toward various acceptors and the effect of beta-N-acetylhexosaminidase on their products suggest that both transferases are UDP-N-acetylglucosamine : alpha-mannoside beta-N-acetylglucosaminyltransferase. Although ovalbumin and glycopeptide V, which was isolated from pronase digest of ovalbumin, were good acceptors, transferase A utilized ovalbumin and glycopeptide V with apparent Km values of 0.44 and 0.33 mM, respectively, whereas the corresponding values for transferase B were 4.5 and 0.050 mM. << Less
-
Control of glycoprotein synthesis. Purification and characterization of rabbit liver UDP-N-acetylglucosamine:alpha-3-D-mannoside beta-1,2-N-acetylglucosaminyltransferase I.
Nishikawa Y., Pegg W., Paulsen H., Schachter H.
UDP-N-acetylglucosamine:alpha-3-D-mannoside beta-1,2-N-acetylglucosaminyltransferase I catalyzes an essential first step in the conversion of high mannose to hybrid and complex N-glycans (Schachter, H. (1986) Biochem. Cell Biol. 64, 163-181; Oppenheimer, C.L., and Hill, R.L. (1981) J. Biol. Chem. ... >> More
UDP-N-acetylglucosamine:alpha-3-D-mannoside beta-1,2-N-acetylglucosaminyltransferase I catalyzes an essential first step in the conversion of high mannose to hybrid and complex N-glycans (Schachter, H. (1986) Biochem. Cell Biol. 64, 163-181; Oppenheimer, C.L., and Hill, R.L. (1981) J. Biol. Chem. 256, 799-804), i.e. the addition of GlcNAc to (Man alpha 1-6(Man alpha 1-3)Man alpha 1-6)(Man alpha 1-3)Man beta 1-4GlcNAc-OR to form (Man alpha 1-6(Man alpha 1-3)Man alpha 1-6)(GlcNAc beta 1-2Man alpha 1-3)Man beta 1-4GlcNAc-OR. The enzyme has been purified from Triton X-100 extracts of rabbit liver by chromatography on CM-Sephadex, Affi-Gel blue, UDP-hexanolamine-Sepharose, and a novel adsorbent in which UDP-GlcNAc is linked to thiopropyl-Sepharose at the 5-position of uracil. The enzyme exists in crude liver extracts in two molecular weight forms separable on Sephadex G-200. The low molecular weight form was purified 64,000-fold with a specific activity of 19.8 mumol/min/mg. The pure enzyme was free of N-acetylglucosaminyltransferase II-V activities. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed a single major band of Mr 45,000 and two minor bands of Mr 54,000 and 50,000. All three bands showed retarded elution from an affinity column in which the acceptor substrate for the transferase was covalently linked to Sepharose. Kinetic analysis indicated a largely ordered sequential mechanism with UDP-GlcNAc binding to the enzyme first and UDP leaving last. Studies with synthetic analogues of the substrate Man alpha 1-6(Man alpha 1-3)Man beta 1-4GlcNAc showed that an unsubstituted equatorial hydroxyl on carbon 4 of the beta-linked Man residue was essential for enzyme activity. << Less
-
Control of glycoprotein synthesis. IX. A terminal Man alpha l-3Man beta 1- sequence in the substrate is the minimum requirement for UDP-N-acetyl-D-glucosamine: alpha-D-mannoside (GlcNAc to Man alpha 1-3) beta 2-N-acetylglucosaminyltransferase I.
Vella G.J., Paulsen H., Schachter H.
Twenty low molecular weight compounds were tested as substrates for UDP-GlcNAc:alpha-D-mannoside (GlcNAc to Man alpha 1-3) beta 2-N-acetylglucosaminyltransferase I (GlcNAc-transferase I) purified from bovine colostrum. This enzyme is at a key control point in the biosynthetic path leading to compl ... >> More
Twenty low molecular weight compounds were tested as substrates for UDP-GlcNAc:alpha-D-mannoside (GlcNAc to Man alpha 1-3) beta 2-N-acetylglucosaminyltransferase I (GlcNAc-transferase I) purified from bovine colostrum. This enzyme is at a key control point in the biosynthetic path leading to complex Asn-linked oligosaccharides. The highest activity was obtained with the substrate Man alpha 1-3(R1 alpha 1-6)Man beta 1-R2 where R1 was Man alpha 1-3(Man alpha 1-6)Man-(Km = 0.20 mM) and R2 was -4GlcNAc beta 1-4GlcNAc-Asn. Somewhat less effective were substrates in which R1 was Man-(Km = 0.4-0.6 mM) and R2 was either-4GlcNAc or -4GlcNAc beta 1-4(Fuc alpha 1-6)GlcNAc-Asn. Removal of the Man alpha 1-6 arm (R1 = H-) or replacing R2 with an isopropyl group had no effect on Vmax but increased the Km about 10-fold, thereby leading to an 85% reduction in enzyme activity as measured under standard conditions. An 85% reduction in activity was also observed if R2 was replaced with N-acetylglucosaminitol. Enzyme activity was reduced 33% if R1 was Gal beta 1-4GlcNAc beta 1-2Man-. Any compounds lacking a Man alpha 1-3-terminus or in which the beta-linked Man had been replaced with an alpha-linked Man were totally inactive. It was concluded that a terminal Man alpha 1-3Man beta 1-sequence is a minimal structural requirement for a GlcNAc-transferase I substrate. The only effective substrate for partially purified UDP-GlcNAc:alpha-D-mannoside (GlcNAc to Man alpha 1-6) beta 2-N-acetylglucosaminyltransferase II (GlcNAc-transferase II) from bovine colostrum was R1-GlcNAc beta 1-2Man alpha 1-3(Man alpha 1-6)Man beta 1-R2 where R1 = H-. The absence of a terminal GlcNAc beta 1-2-residue or masking this residue by making R1 = Gal beta 1-4-, both prevented enzyme activity, indicating that GlcNAc-transferase I action must precede GlcNAc-transferase II action during biosynthesis of complex Asn-linked oligosaccharides. << Less
Can J Biochem Cell Biol 62:409-417(1984) [PubMed] [EuropePMC]
-
Purification and characterization of a rabbit liver alpha 1 goes to 3 mannoside beta 1 goes to 2 N-acetylglucosaminyltransferase.
Oppenheimer C.L., Hill R.L.
An alpha 1 goes to 3 mannoside beta 1 goes to 2 N-acetylglucosaminyltransferase has been purified 7000-fold in 36% yield from a Triton X-100 extract of rabbit liver acetone powder by affinity chromatography on UDP-hexanolamine agarose. Sodium dodecyl sulfate gel electrophoresis of the purified enz ... >> More
An alpha 1 goes to 3 mannoside beta 1 goes to 2 N-acetylglucosaminyltransferase has been purified 7000-fold in 36% yield from a Triton X-100 extract of rabbit liver acetone powder by affinity chromatography on UDP-hexanolamine agarose. Sodium dodecyl sulfate gel electrophoresis of the purified enzyme revealed two major bands with molecular weights of 58,000 and 46,000. Examination of the acceptor substrate specificity with pure oligomannosides revealed that the best acceptor had the following structure, (Formula: see text) and gave a single product in which N-acetylglucosamine was present in the sequence GlcNAc beta 1 goes to 2Man alpha 1 goes to 3Man beta 1 goes to 4 GlcNAc. Other terminal mannose residues in the best acceptor as well as that linked alpha 1 goes to 6 in the following oligosaccharide, (Formula: see text) were not acceptors. This specificity is in accord with the role of the transferase in the processing of mannose-containing oligosaccharides during glycoprotein biosynthesis. << Less
-
The nonidentity of porcine N-acetylglucosaminyltransferases I and II.
Oppenheimer C.L., Eckhardt A.E., Hill R.L.
J Biol Chem 256:11477-11482(1981) [PubMed] [EuropePMC]
This publication is cited by 1 other entry.
-
Isolation and properties of alpha-D-mannose:beta-1,2-N-acetylglucosaminyltransferase from trachea mucosa.
Mendicino J., Chandrasekaran E.V., Anumula K.R., Davila M.
A beta-1,2-N-acetylglucosaminyltransferase which transfers N-acetylglucosamine from UDP-N-acetylglucosamine to the branched terminal mannosyl residues found in the complex type oligosaccharide units of N-linked glycoproteins was isolated from swine trachea mucosa. The enzyme was purified from micr ... >> More
A beta-1,2-N-acetylglucosaminyltransferase which transfers N-acetylglucosamine from UDP-N-acetylglucosamine to the branched terminal mannosyl residues found in the complex type oligosaccharide units of N-linked glycoproteins was isolated from swine trachea mucosa. The enzyme was purified from microsomes after solubilization with 1% Triton X-100 and 1% Nonidet P-40, and it was also isolated from a soluble extract of this tissue. The enzyme was purified by chromatography on DEAE-cellulose, cellulose phosphate, and Sephacryl S300 columns and by affinity chromatography on a Sepharose 4B column containing covalently bound ovomucoid. The purified enzyme forms beta-1,2 bonds between N-acetylglucosamine and terminal-branched mannosyl residues of glycoproteins and glycopeptides. The enzyme has an absolute specificity for terminal branched mannosyl residues, and solute specificity for terminal branched mannosyl residues, and no activity is observed with mannose, p-nitrophenyl alpha-D-mannoside, p-nitrophenyl beta-O-mannoside, and glycopeptides which contain unbranched oligosaccharide chains terminating in free mannose. Evidence obtained by kinetic and structural analysis shows that the purified enzyme catalyzes the reactions shown in Scheme I. << Less
Biochemistry 20:967-976(1981) [PubMed] [EuropePMC]
This publication is cited by 1 other entry.
-
Independent Lec1A CHO glycosylation mutants arise from point mutations in N-acetylglucosaminyltransferase I that reduce affinity for both substrates. Molecular consequences based on the crystal structure of GlcNAc-TI.
Chen W., Unligil U.M., Rini J.M., Stanley P.
A key enzyme in regulating the maturation of N-linked glycans is UDP-N-acetylglucosamine:alpha-3-D-mannoside beta-1,2-N-acetylglucosaminyltransferase I (GlcNAc-TI, EC 2.4.1.101). Lec1 CHO cells lack GlcNAc-TI activity and synthesize only the oligomannosyl class of N-glycans. By contrast, Lec1A CHO ... >> More
A key enzyme in regulating the maturation of N-linked glycans is UDP-N-acetylglucosamine:alpha-3-D-mannoside beta-1,2-N-acetylglucosaminyltransferase I (GlcNAc-TI, EC 2.4.1.101). Lec1 CHO cells lack GlcNAc-TI activity and synthesize only the oligomannosyl class of N-glycans. By contrast, Lec1A CHO mutants have weak GlcNAc-TI activity due to the reduced affinity of GlcNAc-TI for both the UDP-GlcNAc and Man(5)GlcNAc(2)Asn substrates. Lec1A CHO mutants synthesize hybrid and complex N-glycans, albeit in reduced amounts compared to parental CHO cells. In this paper, we identify two point mutations that gave rise to the Lec1A phenotype in three independent Lec1A CHO mutants. The G634A mutation in Lec1A.2C converts an aspartic acid to an asparagine at amino acid 212, disrupting a conserved DXD motif (E(211)DD(213) in all GlcNAc-TIs) that makes critical interactions with bound UDP-GlcNAc and Mn(2+) ion in rabbit GlcNAc-TI. The C907T mutation in Lec1A.3E and Lec1A.5J converts an arginine conserved in all GlcNAc-TIs to a tryptophan at amino acid 303, altering interactions that are important in stabilizing a critical structural element in rabbit GlcNAc-TI. Correction of each mutation by site-directed mutagenesis restored their GlcNAc-TI activity and lectin binding properties to parental levels. The effect of the two amino acid changes on GlcNAc-TI catalysis is discussed in relation to the crystal structure of rabbit GlcNAc-TI complexed with manganese and UDP-GlcNAc. << Less
-
Glycosyltransferases involved in elongation of N-glycosidically linked oligosaccharides of the complex or N-acetyllactosamine type.
Schachter H., Narasimhan S., Gleeson P., Vella G.
Methods Enzymol 98:98-134(1983) [PubMed] [EuropePMC]
This publication is cited by 9 other entries.