Document Detail

Stochastic inhibitor release and binding from single-enzyme molecules.
MedLine Citation:
PMID:  17965235     Owner:  NLM     Status:  MEDLINE    
Inhibition kinetics of single-beta-galactosidase molecules with the slow-binding inhibitor d-galactal have been characterized by segregating individual enzyme molecules in an array of 50,000 ultra small reaction containers and observing substrate turnover changes with fluorescence microscopy. Inhibited and active states of beta-galactosidase could be clearly distinguished, and the large array size provided very good statistics. With a pre-steady-state experiment, we demonstrated the stochastic character of inhibitor release, which obeys first-order kinetics. Under steady-state conditions, the quantitative detection of substrate turnover changes over long time periods revealed repeated inhibitor binding and release events, which are accompanied by conformational changes of the enzyme's catalytic site. We proved that the rate constants of inhibitor release and binding derived from stochastic changes in the substrate turnover are consistent with bulk-reaction kinetics.
Hans H Gorris; David M Rissin; David R Walt
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Publication Detail:
Type:  Journal Article     Date:  2007-10-26
Journal Detail:
Title:  Proceedings of the National Academy of Sciences of the United States of America     Volume:  104     ISSN:  0027-8424     ISO Abbreviation:  Proc. Natl. Acad. Sci. U.S.A.     Publication Date:  2007 Nov 
Date Detail:
Created Date:  2007-11-07     Completed Date:  2008-01-28     Revised Date:  2013-06-06    
Medline Journal Info:
Nlm Unique ID:  7505876     Medline TA:  Proc Natl Acad Sci U S A     Country:  United States    
Other Details:
Languages:  eng     Pagination:  17680-5     Citation Subset:  IM    
Department of Chemistry, Tufts University, 62 Talbot Avenue, Medford, MA 02155, USA.
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MeSH Terms
Enzyme Inhibitors / chemistry,  metabolism*
Enzymes / chemistry,  metabolism*
Galactosides / chemistry,  metabolism
Microscopy, Fluorescence / methods
Stochastic Processes
beta-Galactosidase / antagonists & inhibitors*,  chemistry*,  metabolism
Reg. No./Substance:
0/Enzyme Inhibitors; 0/Enzymes; 0/Galactosides; EC

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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