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: UMLS:C0268318 (
ICP
)
10,007
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The formation of methylarsonous acid (MAs
III
) and dimethylarsinous acid (DMAs
III
) in the course of inorganic arsenic (iAs) metabolism plays an important role in the adverse effects of chronic exposure to iAs. High-performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) and hydride generation-cryotrapping-atomic absorption spectrometry (HG-CT-AAS) have been frequently used for the analysis of MAs
III
and DMAs
III
in biological samples. While HG-CT-AAS has consistently detected MAs
III
and DMAs
III
, HPLC-
ICP
-MS analyses have provided inconsistent and contradictory results. This study compares the capacities of both methods to detect and quantify MAs
III
and DMAs
III
in an
in vitro
methylation system consisting of recombinant human arsenic (+3 oxidation state) methyltransferase (
AS3MT
), S-adenosylmethionine as a methyl donor, a non-thiol reductant tris(2-carboxyethyl)phosphine, and arsenite (iAs
III
) or MAs
III
as substrate. The results show that reversed-phase HPLC-
ICP
-MS can identify and quantify MAs
III
and DMAs
III
in aqueous mixtures of biologically relevant arsenical standards. However, HPLC separation of the
in vitro
methylation mixture resulted in significant losses of MAs
III
, and particularly DMAs
III
with total arsenic recoveries below 25%. Further analyses showed that MAs
III
and DMAs
III
bind to
AS3MT
or interact with other components of the methylation mixture, forming complexes that do not elute from the column. Oxidation of the mixture with H
2
O
2
which converted trivalent arsenicals to their pentavalent analogs prior to HPLC separation increased total arsenic recoveries to ~95%. In contrast, HG-CT-AAS analysis found large quantities of methylated trivalent arsenicals in mixtures incubated with either iAs
III
or MAs
III
and provided high (>72%) arsenic recoveries. These data suggest that an HPLC-based analysis of biological samples can underestimate MAs
III
and DMAs
III
concentrations and that controlling for arsenic species recovery is essential to avoid artifacts.
...
PMID:Comparative oxidation state specific analysis of arsenic species by high-performance liquid chromatography-inductively coupled plasma-mass spectrometry and hydride generation-cryotrapping-atomic absorption spectrometry. 2368 1
