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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
1
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pubmed:dateCreated |
1987-4-27
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pubmed:abstractText |
Radiolabeling of human liver alpha-L-fucosidase (alpha-L-fucoside fucohydrolase, EC 3.2.1.51) with [1-3H]conduritol C trans-epoxide revealed that there are four active sites per tetrameric enzyme complex. Solvent isotope effect experiments give evidence for a proton transfer at the rate-limiting step in catalysis. Transglycosylase activity was observed using methanol as an alternative glycone acceptor to produce methyl alpha-L-fucoside, suggesting that alpha-L-fucose is formed when water is the acceptor. Initial burst kinetics experiments suggest that a glycosyl-enzyme intermediate is formed, although the magnitude of the burst is not stoichiometric with the number of active sites. These data, along with previous results, suggest a general acid-general base catalytic mechanism involving double inversion of stereochemistry at C-1 of fucose, as well as the formation of either a covalent glycosyl-enzyme intermediate or a tight ion pair between a charged active-site residue and a hypothetical fucosyl oxocarbonium ion intermediate.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Mar
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pubmed:issn |
0006-3002
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
18
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pubmed:volume |
912
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
132-8
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:3828350-Affinity Labels,
pubmed-meshheading:3828350-Binding Sites,
pubmed-meshheading:3828350-Catalysis,
pubmed-meshheading:3828350-Glycosylation,
pubmed-meshheading:3828350-Humans,
pubmed-meshheading:3828350-Hydrogen-Ion Concentration,
pubmed-meshheading:3828350-Kinetics,
pubmed-meshheading:3828350-Liver,
pubmed-meshheading:3828350-Solvents,
pubmed-meshheading:3828350-alpha-L-Fucosidase
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pubmed:year |
1987
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pubmed:articleTitle |
Further studies on the catalytic mechanism of human liver alpha-L-fucosidase.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
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