Linked Life Data

16171396

Source:http://linkedlifedata.com/resource/pubmed/id/16171396

Statements in which the resource exists.
SubjectPredicateObjectContext
pubmed-article:16171396rdf:typepubmed:Citationlld:pubmed
pubmed-article:16171396lifeskim:mentionsumls-concept:C0015576lld:lifeskim
pubmed-article:16171396lifeskim:mentionsumls-concept:C0001057lld:lifeskim
pubmed-article:16171396lifeskim:mentionsumls-concept:C0017976lld:lifeskim
pubmed-article:16171396lifeskim:mentionsumls-concept:C1522508lld:lifeskim
pubmed-article:16171396lifeskim:mentionsumls-concept:C0007382lld:lifeskim
pubmed-article:16171396lifeskim:mentionsumls-concept:C0683941lld:lifeskim
pubmed-article:16171396lifeskim:mentionsumls-concept:C0441712lld:lifeskim
pubmed-article:16171396pubmed:issue38lld:pubmed
pubmed-article:16171396pubmed:dateCreated2005-9-20lld:pubmed
pubmed-article:16171396pubmed:abstractTextBeta-N-acetylglucosaminidases are commonly occurring enzymes involved in the degradation of polysaccharides and glycoconjugates containing N-acetylglucosamine residues. Such enzymes have been classified into glycoside hydrolase families 3 and 20 and are believed to follow distinct chemical mechanisms. Family 3 enzymes are thought to follow a standard retaining mechanism involving a covalent glycosyl enzyme intermediate while family 20 enzymes carry out a substrate-assisted mechanism involving the transient formation of an enzyme-sequestered oxazoline or oxazolinium ion intermediate. Detailed mechanistic analysis of representatives of these two families provides support for these mechanisms as well as detailed insights into transition state structure. Alpha-secondary deuterium kinetic isotope effects of kH/kD = 1.07 and 1.10 for Streptomyces plicatus beta-hexosaminidase (SpHex) and Vibrio furnisii beta-N-acetylglucosaminidase (ExoII) respectively indicate transition states with oxocarbenium ion character in each case. Brønsted plots for hydrolysis of a series of aryl hexosaminides are quite different in the two cases. For SpHex a large degree of proton donation is suggested by the relatively low value of beta(lg) (-0.29) on kcat/Km, compared with a beta(lg) of -0.79 for ExoII. Most significantly the Taft plots derived from kinetic parameters for a series of p-nitrophenyl N-acyl glucosaminides bearing differing levels of fluorine substitution in the N-acyl group are completely different. A very strong dependence (slope = -1.29) is seen for SpHex, indicating direct nucleophilic participation by the acetamide, while essentially no dependence (0.07) is seen for ExoII, suggesting that the acetamide plays purely a binding role. Taken together these data provide unprecedented insight into enzymatic glycosyl transfer mechanisms wherein the structures of both the nucleophile and the leaving group are systematically varied.lld:pubmed
pubmed-article:16171396pubmed:languageenglld:pubmed
pubmed-article:16171396pubmed:journalhttp://linkedlifedata.com/r...lld:pubmed
pubmed-article:16171396pubmed:citationSubsetIMlld:pubmed
pubmed-article:16171396pubmed:chemicalhttp://linkedlifedata.com/r...lld:pubmed
pubmed-article:16171396pubmed:chemicalhttp://linkedlifedata.com/r...lld:pubmed
pubmed-article:16171396pubmed:chemicalhttp://linkedlifedata.com/r...lld:pubmed
pubmed-article:16171396pubmed:chemicalhttp://linkedlifedata.com/r...lld:pubmed
pubmed-article:16171396pubmed:statusMEDLINElld:pubmed
pubmed-article:16171396pubmed:monthSeplld:pubmed
pubmed-article:16171396pubmed:issn0006-2960lld:pubmed
pubmed-article:16171396pubmed:authorpubmed-author:WithersStephe...lld:pubmed
pubmed-article:16171396pubmed:authorpubmed-author:VocadloDavid...lld:pubmed
pubmed-article:16171396pubmed:issnTypePrintlld:pubmed
pubmed-article:16171396pubmed:day27lld:pubmed
pubmed-article:16171396pubmed:volume44lld:pubmed
pubmed-article:16171396pubmed:ownerNLMlld:pubmed
pubmed-article:16171396pubmed:authorsCompleteYlld:pubmed
pubmed-article:16171396pubmed:pagination12809-18lld:pubmed
pubmed-article:16171396pubmed:dateRevised2007-11-15lld:pubmed
pubmed-article:16171396pubmed:meshHeadingpubmed-meshheading:16171396...lld:pubmed
pubmed-article:16171396pubmed:meshHeadingpubmed-meshheading:16171396...lld:pubmed
pubmed-article:16171396pubmed:meshHeadingpubmed-meshheading:16171396...lld:pubmed
pubmed-article:16171396pubmed:meshHeadingpubmed-meshheading:16171396...lld:pubmed
pubmed-article:16171396pubmed:meshHeadingpubmed-meshheading:16171396...lld:pubmed
pubmed-article:16171396pubmed:meshHeadingpubmed-meshheading:16171396...lld:pubmed
pubmed-article:16171396pubmed:meshHeadingpubmed-meshheading:16171396...lld:pubmed
pubmed-article:16171396pubmed:meshHeadingpubmed-meshheading:16171396...lld:pubmed
pubmed-article:16171396pubmed:meshHeadingpubmed-meshheading:16171396...lld:pubmed
pubmed-article:16171396pubmed:year2005lld:pubmed
pubmed-article:16171396pubmed:articleTitleDetailed comparative analysis of the catalytic mechanisms of beta-N-acetylglucosaminidases from families 3 and 20 of glycoside hydrolases.lld:pubmed
pubmed-article:16171396pubmed:affiliationDepartment of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada.lld:pubmed
pubmed-article:16171396pubmed:publicationTypeJournal Articlelld:pubmed
pubmed-article:16171396pubmed:publicationTypeComparative Studylld:pubmed
http://linkedlifedata.com/r...pubmed:referesTopubmed-article:16171396lld:pubmed
http://linkedlifedata.com/r...pubmed:referesTopubmed-article:16171396lld:pubmed
http://linkedlifedata.com/r...pubmed:referesTopubmed-article:16171396lld:pubmed
http://linkedlifedata.com/r...pubmed:referesTopubmed-article:16171396lld:pubmed
http://linkedlifedata.com/r...pubmed:referesTopubmed-article:16171396lld:pubmed
http://linkedlifedata.com/r...pubmed:referesTopubmed-article:16171396lld:pubmed