Linked Life Data

2249689

Source:http://linkedlifedata.com/resource/pubmed/id/2249689

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1991-1-11
pubmed:abstractText
The relative contribution of N-glycoloyl-beta-D-neuraminic acid (Neu5Gc) to total sialic acids expressed in mouse and rat liver glycoconjugates was found to be 95% and 11%, respectively. This considerable difference in sialic acid composition made these two tissues suitable models for a comparative investigation into the regulation of Neu5Gc biosynthesis and utilization. An examination of the CMP-glycoside specificity of Golgi-associated sialyltransferases using CMP-N-acetyl-beta-D-neuraminic acid (CMP-Neu5Ac) and CMP-Neu5Gc revealed no significant tissue-dependent differences. The Golgi membrane CMP-sialic acid transport system from rat liver did, however, exhibit a slightly higher internalisation rate for CMP-Neu5Ac, though no preferential affinity for this sugar nucleotide over CMP-Neu5Gc was observed. In experiments, where Golgi membrane preparations were incubated with an equimolar mixture of labelled CMP-Neu5Ac and CMP-Neu5Gc, no significant tissue-dependent differences in [14C]sialic acid composition were observed, either in the luminal soluble sialic acid fraction or in the precipitable sialic acid fraction, results which are consistent with the above observations. From this experiment, evidence was also obtained for the presence of a Golgi-lumen-associated CMP--sialic acid hydrolase which exhibited no apparent specificity for either CMP-Neu5Ac or CMP-Neu5Gc. The specific activity of the CMP-Neu5Ac hydroxylase, the enzyme responsible for the biosynthesis of Neu5Gc, was found to be 28-fold greater in high-speed supernatants of mouse liver than of rat liver. No hydroxylase activity was detected in the Golgi membrane preparations. It is therefore proposed that the cytoplasmic ratio of CMP-Neu5Ac and CMP-Neu5Gc produced by the hydroxylase, remains largely unmodified after CMP-glycoside uptake into the Golgi apparatus and transfer on to growing glycoconjugate glycan chains. The close relationship between the total sialic acid composition and the sialic acid pattern in the CMP-glycoside pools of the tissues lends considerable weight to this hypothesis.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0014-2956
pubmed:author
pubmed:issnType
Print
pubmed:day
13
pubmed:volume
193
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
715-23
pubmed:dateRevised
2007-7-23
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
A study on the regulation of N-glycoloylneuraminic acid biosynthesis and utilization in rat and mouse liver.
pubmed:affiliation
Laboratoire de Chimie Biologique, Centre National de Recherche Scientifique no. 111, Université de Sciences et Techniques de Lille Flandres-Artois, Villeneuve d'Ascq, France.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't