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

Carbohydrate-deficient transferrin (CDT) is now considered to be the most sensitive and specific biological marker of alcohol abuse. However, the mechanism by which chronic alcohol consumption causes an elevation of CDT levels in serum is still not understood. Therefore, we fed eight pairs of male rats a nutritionally adequate liquid diet containing either alcohol (36% of energy) or isocaloric dextrose (control) for 4 weeks, after which blood and liver samples were obtained. Serum CDT content in alcohol-treated rats increased by 45% (P < .05) in ethanol-fed animals compared with their corresponding controls. In contrast, in rats fed ethanol, the activities of sialyltransferase (ST), galactosyltransferase (GT), and N-acetylglucosamine transferase (N-AGT), which are glycosyltransferases involved in transferrin carbohydrate side chain synthesis, were diminished by 24% and 40% (P < .05), 23% and 51% (P < .05, .001), and 20% and 26% (P < .05) in total liver homogenates and Golgi fraction (GF) 1, respectively, when expressed as units/100 g body weight. These enzymes were also significantly less active in hepatic GFs 2 and 3. The depression of the transferase activities in ethanol-fed rats appeared to be due, at least in part, to enzyme inactivation by acetaldehyde, whereas ethanol itself was without effect. Similar results were obtained in humans: five alcohol abusers were found to exhibit a 23% decrease in hepatic sialyltransferase and a 41% increase in sialidase activities, respectively, when compared with three nondrinking subjects.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Serum carbohydrate-deficient transferrin: mechanism of increase after chronic alcohol intake. 759 Jun 64

The effects of acute ethanol intoxication on the glycoprotein metabolism of rat liver Golgi apparatus have been investigated. A marked reduction of the galactosyltransferase and sialyltransferase activities was observed in Golgi membranes 6 h after ethanol administration (6g/Kg body wt) together with the retention of glycoproteins in the hepatocyte. Methylpyrazole, an inhibitor of alcohol dehydrogenase, administrated "in vivo" (10 mg/Kg body wt) prevented the ethanol-induced inhibition of both the transferase activities. Acetaldehyde formed "in vitro" unstable and stable adducts with Golgi membrane proteins and with purified galactosyltransferase. These results suggest that the impairment of glycoprotein metabolism at the level of liver Golgi apparatus may be mediated, at least in part, through the acetaldehyde formation during ethanol oxidation.
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PMID:Acetaldehyde-induced impairment of protein glycosylation in liver Golgi apparatus. 833 19