Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.53 (sialidase)
 2,694 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An antibody-lectin enzyme immunoassay (EIA) technique was developed for the analysis of sugar chains of serum alpha-fetoprotein in various liver diseases. The anti-'alpha-fetoprotein'-IgG was coated on a microtiter plate and then treated with periodic acid. A serum sample was added to the plate and then a 'peroxidase'-conjugated lectin was added. The amount of lectin bound to the sugar chain of the 'alpha-fetoprotein' was estimated from the 'peroxidase' activity. The 'peroxidase' activities of 4 different lectins, LCA, Con A, LCA and EPHA, were compared. The LCA/'wheat germ agglutinin' activity ratio and LCA/EPHA activity ratio were increased in liver diseases and LCA/'wheat germ agglutinin' ratio showed a statistically significant difference between the chronic hepatitis and the liver cirrhosis groups (p less than 0.05). Furthermore, when serum samples were pretreated with sialidase, a statistically significant difference was observed in the LCA/EPHA and LCA/Con A ratios between the chronic hepatitis and the hepatoma groups (p less than 0.05). These results indicated that low sialylation at the non-reduced end of the sugar chains of 'alpha-fetoprotein' occurs in liver cirrhosis and that high fucosylation at the reduced end of N-acetylglucosamine residue of 'alpha-fetoprotein' occurs in hepatomas.
 ...
PMID:Alpha-fetoprotein antibody-lectin enzyme immunoassay to characterize sugar chains for the study of liver diseases. 246 50

Serum alpha-fetoprotein (AFP) is a glycoprotein of which the sugar chain is considered to show structural changes with malignancies. Microheterogeneity of the serum AFP carbohydrate structure was studied in samples from 35 patients with benign and malignant diseases. Sera were digested directly, extensively, and sequentially with sialidase. beta-galactosidase and beta-N-acetylhexosaminidase. Before and after digestion, sera were examined by means of lectin affinity electrophoresis using eight lectins. Relationships between AFP carbohydrate structures and liver diseases were elucidated by the lectin-reactive profiles and the effect of glycosidase digestion. More than 94% of the AFP carbohydrate structures found in patients with benign and malignant liver diseases were biantennary complex-type oligosaccharides. Changes in the AFP carbohydrate structures at the early stage of hepatocellular carcinoma revealed the addition of alpha 1-->6 fucose to the reducing terminal N-acetylglucosamine and monosialylated AFPs. In both advanced hepatocellular carcinoma and AFP producing extrahepatic malignancies, AFP carbohydrate structures were characterized as the further addition of beta 1-->4 N-acetylglucosamine and heterogeneity in the galactose and N-acetylglucosamine residues. Sequential glycosidase digestion and lectin affinity electrophoresis is useful for analysing the carbohydrate structures of serum glycoprotein.
 ...
PMID:Comparison of carbohydrate structures of serum alpha-fetoprotein by sequential glycosidase digestion and lectin affinity electrophoresis. 889 7