Document Detail


A novel S-adenosyl-L-methionine:arsenic(III) methyltransferase from rat liver cytosol.
MedLine Citation:
PMID:  11790780     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
S-Adenosyl-l-methionine (AdoMet):arsenic(III) methyltransferase, purified from liver cytosol of adult male Fischer 344 rats, catalyzes transfer of a methyl group from AdoMet to trivalent arsenicals producing methylated and dimethylated arsenicals. The kinetics of production of methylated arsenicals in reaction mixtures containing enzyme, AdoMet, dithiothreitol, glutathione (GSH), and arsenite are consistent with a scheme in which monomethylated arsenical produced from arsenite is the substrate for a second methylation reaction that yields dimethylated arsenical. The mRNA for this protein predicts a 369-amino acid residue protein (molecular mass 41056) that contains common methyltransferase sequence motifs. Its sequence is similar to Cyt19, a putative methyltransferase, expressed in human and mouse tissues. Reverse transcription-polymerase chain reaction detects S-adenosyl-l-methionine:arsenic(III) methyltransferase mRNA in rat tissues and in HepG2 cells, a human cell line that methylates arsenite and methylarsonous acid. S-Adenosyl-l-methionine:arsenic(III) methyltransferase mRNA is not detected in UROtsa cells, an immortalized human urothelial cell line that does not methylate arsenite. Because methylation of arsenic is a critical feature of its metabolism, characterization of this enzyme will improve our understanding of this metalloid's metabolism and its actions as a toxin and a carcinogen.
Authors:
Shan Lin; Qing Shi; F Brent Nix; Miroslav Styblo; Melinda A Beck; Karen M Herbin-Davis; Larry L Hall; Josef B Simeonsson; David J Thomas
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.     Date:  2002-01-14
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  277     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2002 Mar 
Date Detail:
Created Date:  2002-03-25     Completed Date:  2002-05-10     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  10795-803     Citation Subset:  IM    
Affiliation:
Curriculum in Toxicology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
Data Bank Information
Bank Name/Acc. No.:
GENBANK/AF393243
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MeSH Terms
Descriptor/Qualifier:
Amino Acid Sequence
Animals
Base Sequence
Cell Line, Transformed
Chromatography, Gel
Cytosol / enzymology*
DNA, Complementary
Humans
Kinetics
Liver / enzymology*
Male
Methyltransferases / chemistry,  genetics,  isolation & purification*,  metabolism
Molecular Sequence Data
RNA, Messenger / genetics,  metabolism
Rats
Rats, Inbred F344
Reverse Transcriptase Polymerase Chain Reaction
Sequence Homology, Amino Acid
Substrate Specificity
Grant Support
ID/Acronym/Agency:
DK56350/DK/NIDDK NIH HHS; ES09941/ES/NIEHS NIH HHS
Chemical
Reg. No./Substance:
0/DNA, Complementary; 0/RNA, Messenger; EC 2.1.1.-/Methyltransferases; EC 2.1.1.-/S-adenosyl-L-methionine arsenic(III) methyltransferase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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