dc.contributor.author | Shen, YQ | |
dc.contributor.author | Tiralongo, J | |
dc.contributor.author | Iwersen, M | |
dc.contributor.author | Sipos, B | |
dc.contributor.author | Kalthoff, H | |
dc.contributor.author | Schauer, R | |
dc.date.accessioned | 2017-05-03T14:17:02Z | |
dc.date.available | 2017-05-03T14:17:02Z | |
dc.date.issued | 2002 | |
dc.date.modified | 2008-02-14T08:10:17Z | |
dc.identifier.issn | 1431-6730 | |
dc.identifier.uri | http://hdl.handle.net/10072/16677 | |
dc.description.abstract | Sialic acids present on human colonic mucins are highly O-acetylated, however, little is known about the underlying enzymatic activity required for O-acetylation in this tissue. Here we report on the substrate specificity, subcellular localization and characterization of the sialate-7(9)-O-acetyltransferase in normal human colonic mucosa. Using CMP-Neu5Ac, the most efficient acceptor substrate of all those tested, the enzymatic activity was found to be optimal at 37 ì with a pH optimum of 7.0. Activity was also found to be dependent on protein, CMP-Neu5Ac (Km: 59.2 卩 and AcCoA (Km: 6.1 卩 concentrations, as well as membrane integrity. The enzyme's activity could be inhibited by CoA with a Ki of 11.9 卮 In addition, enzymatic activity was found to be localized in the Golgi-enriched membrane fraction. The nature of the O-acetylated products formed were verified with the aid of chromatographic and enzymatic techniques. The main product was 9-O-acetylated Neu5Ac, with a significant amount of oligo-O-acetylated Neu5Ac also being detected. The utilization of CMP-Neu5Ac as the acceptor substrate was confirmed by the isolation and characterization of the putative product, CMP-Neu5,9Ac2, using ion-exchange chromatography. The ability of CMP-Neu5,9Ac2 to act as a sialic acid donor for sialyltransferases represents the conclusive demonstration for the formation of CMP-Neu5,9Ac2. | |
dc.description.peerreviewed | Yes | |
dc.description.publicationstatus | Yes | |
dc.language | English | |
dc.language.iso | eng | |
dc.publisher | Walter de Gruyter | |
dc.publisher.place | Germany | |
dc.relation.ispartofpagefrom | 307 | |
dc.relation.ispartofpageto | 317 | |
dc.relation.ispartofjournal | Biological Chemistry | |
dc.relation.ispartofvolume | 383 | |
dc.subject.fieldofresearch | Biochemistry and cell biology | |
dc.subject.fieldofresearchcode | 3101 | |
dc.title | Characterization of the sialate-7(9)-O-acetyltransferase from the microsomes of human colonic mucosa | |
dc.type | Journal article | |
dc.type.description | C1 - Articles | |
dc.type.code | C - Journal Articles | |
gro.date.issued | 2002 | |
gro.hasfulltext | No Full Text | |
gro.griffith.author | Tiralongo, Joe | |