Publication Date:
1989-03-17
Description:
A true Bronsted analysis of proton transfer in an enzyme mechanism is made possible by the chemical rescue of an inactive mutant of aspartate aminotransferase, where the endogenous general base, Lys258, is replaced with Ala by site-directed mutagenesis. Catalytic activity is restored to this inactive mutant by exogenous amines. The eleven amines studied generate a Bronsted correlation with beta of 0.4 for the transamination of cysteine sulfinate, when steric effects are included in the regression analysis. Localized mutagenesis thus allows the classical Bronsted analysis of transition-state structure to be applied to enzyme-catalyzed reactions.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Toney, M D -- Kirsch, J F -- GM07232/GM/NIGMS NIH HHS/ -- GM35393/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1989 Mar 17;243(4897):1485-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, University of California, Berkeley 94720.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2538921" target="_blank"〉PubMed〈/a〉
Keywords:
Amines
;
Aspartate Aminotransferases/*metabolism
;
Binding Sites
;
Catalysis
;
Escherichia coli/enzymology
;
Kinetics
;
Lysine
;
Mutation
;
Protons
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
