Publication: Ni 2 +-activated glyoxalase i from Escherichia coli: Substrate specificity, kinetic isotope effects and evolution within the βαβββ superfamily
Issued Date
2012-03-01
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ISSN
18733344
01620134
01620134
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2-s2.0-84858445695
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Mahidol University
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SCOPUS
Bibliographic Citation
Journal of Inorganic Biochemistry. Vol.108, (2012), 133-140
Suggested Citation
Kadia Y. Mullings, Nicole Sukdeo, Uthaiwan Suttisansanee, Yanhong Ran, John F. Honek Ni 2 +-activated glyoxalase i from Escherichia coli: Substrate specificity, kinetic isotope effects and evolution within the βαβββ superfamily. Journal of Inorganic Biochemistry. Vol.108, (2012), 133-140. doi:10.1016/j.jinorgbio.2011.11.008 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/13790
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Title
Ni 2 +-activated glyoxalase i from Escherichia coli: Substrate specificity, kinetic isotope effects and evolution within the βαβββ superfamily
Abstract
The Escherichia coli glyoxalase system consists of the metalloenzymes glyoxalase I and glyoxalase II. Little is known regarding Ni 2 + -activated E. coli glyoxalase I substrate specificity, its thiol cofactor preference, the presence or absence of any substrate kinetic isotope effects on the enzyme mechanism, or whether glyoxalase I might catalyze additional reactions similar to those exhibited by related βαβ ββ structural superfamily members. The current investigation has shown that this two-enzyme system is capable of utilizing the thiol cofactors glutathionylspermidine and trypanothione, in addition to the known tripeptide glutathione, to convert substrate methylglyoxal to non-toxic d-lactate in the presence of Ni 2 + ion. E. coli glyoxalase I, reconstituted with either Ni 2 + or Cd 2 + , was observed to efficiently process deuterated and non-deuterated phenylglyoxal utilizing glutathione as cofactor. Interestingly, a substrate kinetic isotope effect for the Ni 2 + -substituted enzyme was not detected; however, the proton transfer step was observed to be partially rate limiting for the Cd 2 + -substituted enzyme. This is the first non-Zn 2 + -activated GlxI where a metal ion-dependent kinetic isotope effect using deuterium-labelled substrate has been observed. Attempts to detect a glutathione conjugation reaction with the antibiotic fosfomycin, similar to the reaction catalyzed by the related superfamily member FosA, were unsuccessful when utilizing the E. coli glyoxalase I E56A mutein. © 2011 Elsevier Inc. All rights reserved.