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

A new procedure for a sialidase assay, by bioluminescence, has been developed. The substrate, N- acetylneuraminyllactose (sialyllactose), hydrolysed by the sialidase activity, releases lactose. This lactose is hydrolysed with beta-galactosidase. The released galactose is oxidized with galactose dehydrogenase and NAD. The NADH produced in the last step is measured by a luminescence system, coupling two enzymes, NAD(P)H dehydrogenase (FMN) and luciferase. This microassay, which is specific, rapid, simple and ultra-sensitive, is a measure for amounts as little as (at least) 5 pmol of N-acetylneuraminic acid (corresponding to 0.15 ng of the released sialic acid). It uses commercialized reagents (non-radioisotopic) and avoids interferences common in other procedures. This method has been used for measuring sialidase activity directly on intact virus, avoiding inconvenient modifications produced in the extraction of the enzyme. The specific activity of sialidase of influenza virus X31 (H3N2), determined by this procedure, is 0.65 U/mg of total virus protein.
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PMID:Sialidase assay by luminescence in the low picomole-range of sialic acid. Its application to the measurement of this activity in influenza virus. 673 52

Neuraminidase or sialidase (EC 3.2.1.18, acylneuraminyl hydrolase) from a strain of the influenza virus A (H3N2), identical to the A/Hong Kong/68 (H3N2) strain, has been purified and characterized by electrofocusing; only about 20% of the previous enzymic activity was lost after electrofocusing. The enzyme activity was measured by the peryodate-thiobarbiturate procedure, by the methoxyphenol-antipyrine method, and by spectrophotometry at 340 nm of the NADH produced in the oxidation of the beta-galactose + NAD+; this beta-galactose was released from lactose by beta-galactosidase; and lactose was liberated from N-acetylneuraminyl-lactose by the neuraminidase activity. The results of the interference by some chemical compounds, which are not true inhibitory agents for the enzyme, on the peryodate-thiobarbiturate reaction are indicated, as well as the detection of other compounds which are true inhibitors of this enzyme in vitro. This neuraminidase was able to release sialic acid with linkages alpha 2-3, alpha 2-6 and alpha 2-8 from several substrates, but with very different efficiency. Natural substrates such as the oligosaccharide N-acetylneuraminyl-lactose, glycoproteins (fetuin, bovine horse brain, colominic acid, and synthetic substrates such as 5-N-acetyl-2-O-(3-methoxyphenyl)-alpha-D-neuraminic acid and 2'-(4-methyl umbellyferil)-alpha-D-N-acetylneuraminic acid were hydrolyzed by this enzyme. Finally, the finding of neuraminidase in ovine, equine and porcine platelet is summarized.
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PMID:[Neuraminidase of influenza virus]. 714 96