HYDROLYTIC ENZYMES IN THE METABOLISM OF TOXINS

  • Hammock, Bruce D, (PI)

Project: Research project

Description

To safeguard human and environmental health in a cost effective
manner, we must develop a mechanistic basis for predicting toxic
risk and assessing environmental exposure. We will address aspects
of these goals by developing an understanding of the biochemistry,
regulation, and toxicological significance of hydrolytic pathways of
metabolism. We have targeted two groups of enzymes both of which
are induced by peroxisome proliferators and which add water to
xenobiotics. Since the epoxide functionality is the reactive center
of some of the most dangerous mutagens, carcinogens and toxins
known, the cytosolic epoxide hydrolase (cEH) is targeted in
objective I. Based on our recent isolation of the message and gene
of the cEH, we will examine its regulation and subcellular
targeting. Parallel approaches in photoaffinity labeling, amino
acid modification, enzyme kinetics and site directed mutagenicity
are being used to determine catalytic mechanism. This information
will be used to design more effective substrates and inhibitors.
All of the above technology will be used to test the hypothesis that
the cEH has an endogenous role in the biosynthesis of diols and
tetrahydrofuran diols of a variety of lipids including arachidonic
acid. Similar approaches will be used to assess the in vitro and in
vivo roles of cEH in ameliorating toxicity. Our second objective emphasizes the carboxylesterases which
metabolize esters such as malathion, permethrin and a variety of
pharmaceuticals. Similar techniques will be used. We will purify
hepatic esterases using esterase specific affinity columns that we
have designed based upon potent transition state mimics of the
enzymes. Based on this work we will isolate cDNA and genomic clones
as in objective I and use these to study the regulation of the
enzymes. We are investigating the catalytic mechanism of esterases
relying heavily on production of mutants in the baculovirus
expression system. We are using a new class of spectral substrates
yielding highly sensitive assays to monitor serum and tissue
esterases following xenobiotic exposure. The above information will
be used to extend our appreciation of the role of esterases in the
metabolism on natural and man made toxins.
StatusFinished
Effective start/end date12/1/8010/31/18

Funding

  • National Institutes of Health
  • National Institutes of Health: $387,806.00
  • National Institutes of Health
  • National Institutes of Health: $401,883.00
  • National Institutes of Health: $406,522.00
  • National Institutes of Health: $420,221.00
  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health: $408,939.00
  • National Institutes of Health: $419,745.00
  • National Institutes of Health: $386,980.00
  • National Institutes of Health: $379,471.00
  • National Institutes of Health
  • National Institutes of Health: $317,255.00
  • National Institutes of Health
  • National Institutes of Health: $419,004.00
  • National Institutes of Health: $308,014.00
  • National Institutes of Health
  • National Institutes of Health: $387,875.00
  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health: $422,069.00
  • National Institutes of Health
  • National Institutes of Health: $412,465.00
  • National Institutes of Health
  • National Institutes of Health: $412,478.00
  • National Institutes of Health: $326,773.00
  • National Institutes of Health
  • National Institutes of Health

Fingerprint

Epoxide Hydrolases
Epoxy Compounds
Enzymes
Xenobiotics
Esterases
Oxylipins
Insect Control
Poisons
Pesticides
Health
Insecticides
Mutagens
Herbicides
Hydrolases
Permethrin
Malathion
Genetic Engineering
Technology
Urine
Baculoviridae

ASJC

  • Environmental Science(all)
  • Medicine(all)