Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: UNIPROT:P47989 (
xanthine oxidase
)
8,633
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Post-translational modification of proteins due to exposure to radicals and other reactive species are markers of metabolic and inflammatory oxidative stress such as sepsis. This study uses the nitrone spin-trap DMPO and a combination of immuno-spin trapping and mass spectrometry to identify in vivo products of radical reactions in mice. We report the detection of dose-dependent production of DMPO-
carboxypeptidase B1
(
CPB1
) adducts in the spleens of mice treated with lipopolysaccharide (LPS). Additionally, we report significant detection of DMPO-
CPB1
adducts in mice experiencing normal physiological conditions. Treatments with inhibitors and experiments with knock-out mice indicate that
xanthine oxidase
and endothelial nitric oxide synthase are important sources of the reactive species that lead to
CPB1
adduct formation. We also report a significant loss of
CPB1
activity following LPS challenge in conjunction with an increase in
CPB1
protein accumulation. This suggests the presence of a possible mechanism for
CPB1
activity loss with compensatory protein production.
...
PMID:Immuno-spin trapping of a post-translational carboxypeptidase B1 radical formed by a dual role of xanthine oxidase and endothelial nitric oxide synthase in acute septic mice. 1904 63
LPS-induced sepsis results in oxidative modification and inactivation of
carboxypeptidase B1
(
CPB1
). In this study, immunoprecipitated
CPB1
was probed for tyrosine nitration using monoclonal nitrotyrosine-specific Abs in a murine model of LPS-induced sepsis. Tyrosine nitration of
CPB1
was significantly reduced in the presence of NO synthase (NOS) inhibitors and the
xanthine oxidase
(XO) inhibitor allopurinol and in NOS-3 knockout (KO) mice.
CPB1
tyrosine nitration and loss of activity by the concerted action of NOS-3 and XO were also confirmed in vitro using both the NO donor 3-morpholinosydnonimine and peroxynitrite. Liquid chromatography/tandem mass spectrometry data indicated five sites of tyrosine nitration in vitro including Tyr(248), the tyrosine at the catalytic site. The site- and protein-specific nitration of
CPB1
and the possible high nitration yield to inactivate it were elucidated by confocal microscopy. The studies indicated that
CPB1
colocalized with NOS-3 in the cytosol of sinus-lining cells in the red pulp of the spleen. Further analysis of
CPB1
-immunoprecipitated samples indicated immunoreactivity to a monoclonal NOS-3 Ab, suggesting protein complex formation with
CPB1
. XO and NOS inhibitors and NOS-3 KO mice injected with LPS had decreased levels of C5a in spleens of septic mice, indicating peroxynitrite as a possible cause for
CPB1
functional alteration. Thus,
CPB1
colocalization, coupling, and proximity to NOS-3 in the sinus-lining cells of spleen red pulp could explain the site-specific tyrosine nitration and inactivation of
CPB1
. These results open up new avenues for the investigation of several enzymes involved in inflammation and their site-specific oxidative modifications by protein-protein interactions as well as their role in sepsis.
...
PMID:Site-specific carboxypeptidase B1 tyrosine nitration and pathophysiological implications following its physical association with nitric oxide synthase-3 in experimental sepsis. 1971 11
