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rdf:type |
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lifeskim:mentions |
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pubmed:dateCreated |
1991-12-23
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pubmed:abstractText |
1. 1-Fluoro-D-glucopyranosyl fluoride undergoes pH-independent loss of F- ion at a rate of 1 x 10(-8) s-1 at 50.0 degrees C, some 10(3)-fold slower than alpha-D-glucopyranosyl fluoride and 4 x 10(4)-fold slower than beta-D-glucopyranosyl fluoride. 2. The (inverting) amyloglucosidase II of Aspergillus niger hydrolyses the difluoride according to Michaelis-Menten kinetics (Km 34 mM and kcat. 0.27 s-1), by apparently the same (simple) mechanism by which it hydrolyses alpha-D-glucopyranosyl fluoride (Km 38 mM and kcat. 730 s-1), rather than by the Hehre resynthesis-hydrolysis mechanism used to transform beta-D-glucopyranosyl fluoride. 3. The difluoride is also a substrate for the (inverting) trehalase of pig kidney [Km 17.3 mM and Vmax. 6.2 x 10(-4) relative to alpha-D-glucopyranosyl fluoride (Km 38 mM]). 4. The quantitatively similar effect of fluorine substitution on the one-step enzymic reactions and on the non-enzymic reactions suggests that they go through similar (oxocarbonium-ion-like) transition states. 5. The difluoride is a substrate for the (retaining) beta-glucosidases from Aspergillus wentii (A3 enzyme) and sweet-almond meal (B isoenzyme) and for the retaining alpha-glucosidase from rice: comparison with the appropriate monofluoride reveals a variable rate-retarding effect of the second fluorine atom on kcat./Km that correlates with other measures of oxocarbonium ion character in the transition state. 6. The difluoride is a substrate for the (retaining) alpha-glucosidase from yeast, but also gives an insidious mimicry of active-site-directed irreversible inhibition, which we tentatively attribute either to formation of the non-covalent complex or to the fluoroglucosyl-enzyme increasing the well-known tendency of this enzyme to come out of solution by adsorption on the walls of the vessel.
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pubmed:grant |
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/1953653-14473391,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1953653-156183,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1953653-2191775,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1953653-2620297,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1953653-2719921,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1953653-2722796,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1953653-3087421,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1953653-3100526,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1953653-3111528,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1953653-3286645,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1953653-3888191,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1953653-3955571,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1953653-5009834,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1953653-5584010,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1953653-5722821,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1953653-6204865,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1953653-6787047,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1953653-7104311
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Oct
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pubmed:issn |
0264-6021
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:day |
15
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pubmed:volume |
279 ( Pt 2)
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
587-93
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pubmed:dateRevised |
2009-11-18
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pubmed:meshHeading |
pubmed-meshheading:1953653-Animals,
pubmed-meshheading:1953653-Aspergillus,
pubmed-meshheading:1953653-Aspergillus niger,
pubmed-meshheading:1953653-Glucan 1,4-alpha-Glucosidase,
pubmed-meshheading:1953653-Glucose,
pubmed-meshheading:1953653-Glucosidases,
pubmed-meshheading:1953653-Hydrolysis,
pubmed-meshheading:1953653-Isoenzymes,
pubmed-meshheading:1953653-Kidney,
pubmed-meshheading:1953653-Kinetics,
pubmed-meshheading:1953653-Oryza sativa,
pubmed-meshheading:1953653-Saccharomyces cerevisiae,
pubmed-meshheading:1953653-Substrate Specificity,
pubmed-meshheading:1953653-Swine,
pubmed-meshheading:1953653-Trehalase,
pubmed-meshheading:1953653-alpha-Glucosidases,
pubmed-meshheading:1953653-beta-Glucosidase
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pubmed:year |
1991
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pubmed:articleTitle |
The interaction of 1-fluoro-D-glucopyranosyl fluoride with glucosidases.
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pubmed:affiliation |
Department of Organic Chemistry, University of Bristol, U.K.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
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