Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.4.99.7 (sialyltransferase)
 1,534 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glycosyltransferase activities of highly purified fractions of Golgi apparatus, plasma membrane and endoplasmic reticulum, all from the same homogenates, were analyzed and compared. Additionally, Golgi apparatus were unstacked and the individual cisternae separated into fractions enriched in cis, median and trans elements using the technique of preparative free-flow electrophoresis. Golgi apparatus from both liver and hepatomas were enriched in all glycosyltransferases compared to endoplasmic reticulum and plasma membranes. However, Golgi apparatus from hepatomas showed both elevated fucosyltransferase and galactosyltransferase activities but reduced sialyltransferase and dipeptidyl peptidase IV (DPP IV) activities compared to liver. Activity of N-acetylglucosaminyltransferase was approximately the same in both liver and hepatoma Golgi apparatus. With normal liver, sialyl- and galactosyltransferase activities and DPP IV showed a marked cis-to-trans gradient of activity. Fucosyltransferase was concentrated in two regions of the electrophoretic separations, one corresponding to cis cisternae and one corresponding to trans cisternae. N-Acetylglucosaminyltransferase activity was more widely distributed but the endogenous acceptor activity was predominantly cis. With hepatoma Golgi apparatus, the pattern for DPP IV was similar to that for liver but those of sialyl- and galactosyltransferases differed markedly from liver. Instead of activity increasing cis to trans, the activities for sialyl- and galactosyltransferases decreased. For fucosyltransferases, activity dependent on exogenous acceptor was medial whereas with endogenous acceptor, two activity peaks, cis and trans, still were observed. For N-acetylglucosaminyltransferase the pattern for hepatoma was similar to that for liver. The results indicate alterations in the distribution of glycosyltransferase activities within the Golgi apparatus in hepatotumorigenesis that may reflect altered cell surface glycosylation patterns.
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PMID:Distribution of glycosyltransferases among Golgi apparatus subfractions from liver and hepatomas of the rat. 168 14

To investigate the direct effect of glucocorticoids on sialylation of intestinal brush-border hydrolases, explants of fetal and suckling rat intestine were maintained in serum-free or serum-containing organ culture with or without dexamethasone (Dx). Glucoamylase and dipeptidyl peptidase IV developed in organ culture from 18-day-old fetuses persisted in highly sialylated forms for 8 days irrespective of Dx presence, parallel in vivo development leading to less sialylated forms at the age of 6 days. In postnatal cultures the Dx-stimulated glucoamylase appeared in a new highly sialylated form never seen after the hormone application in vivo. These findings are in agreement with the elevation of bound sialyltransferase (ST) of cultured intestine in protein-free media. In serum-containing medium Dx stimulated the formation and release of soluble ST into the culture medium.
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PMID:Regulation of sialylation of intestinal brush-border enzymes and of sialyltransferase activity in organ cultures by dexamethasone. 207 6