Source:http://linkedlifedata.com/resource/pubmed/id/10660550
Switch to
Predicate | Object |
---|---|
rdf:type | |
lifeskim:mentions | |
pubmed:issue |
6
|
pubmed:dateCreated |
2000-3-16
|
pubmed:abstractText |
Homocysteine thiolactone is formed in all cell types studied thus far as a result of editing reactions of some aminoacyl-tRNA synthetases. Because inadvertent reactions of thiolactone with proteins are potentially harmful, the ability to detoxify homocysteine thiolactone is essential for biological integrity. This work shows that a single specific enzyme, present in mammalian but not in avian sera, hydrolyzes thiolactone to homocysteine. Human serum thiolactonase, a 45-kDa protein component of high density lipoprotein, requires calcium for activity and stability and is inhibited by isoleucine and penicillamine. Substrate specificity studies suggest that homocysteine thiolactone is a likely natural substrate of this enzyme. However, thiolactonase also hydrolyzes non-natural substrates, such as phenyl acetate, p-nitrophenyl acetate, and the organophospate paraoxon. N-terminal amino acid sequence of pure thiolactonase is identical with that of human paraoxonase. These and other data indicate that paraoxonase, an organophosphate-detoxifying enzyme whose natural substrate and function remained unknown up to now, is in fact homocysteine thiolactonase. By detoxifying homocysteine thiolactone, the thiolactonase/paraoxonase would protect proteins against homocysteinylation, a potential contributing factor to atherosclerosis.
|
pubmed:language |
eng
|
pubmed:journal | |
pubmed:citationSubset |
IM
|
pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Amino Acids,
http://linkedlifedata.com/resource/pubmed/chemical/Aryldialkylphosphatase,
http://linkedlifedata.com/resource/pubmed/chemical/Calcium,
http://linkedlifedata.com/resource/pubmed/chemical/Enzyme Inhibitors,
http://linkedlifedata.com/resource/pubmed/chemical/Esterases,
http://linkedlifedata.com/resource/pubmed/chemical/Homocysteine,
http://linkedlifedata.com/resource/pubmed/chemical/Lipoproteins, HDL,
http://linkedlifedata.com/resource/pubmed/chemical/Penicillamine,
http://linkedlifedata.com/resource/pubmed/chemical/homocysteine thiolactone
|
pubmed:status |
MEDLINE
|
pubmed:month |
Feb
|
pubmed:issn |
0021-9258
|
pubmed:author | |
pubmed:issnType |
Print
|
pubmed:day |
11
|
pubmed:volume |
275
|
pubmed:owner |
NLM
|
pubmed:authorsComplete |
Y
|
pubmed:pagination |
3957-62
|
pubmed:dateRevised |
2006-11-15
|
pubmed:meshHeading |
pubmed-meshheading:10660550-Amino Acids,
pubmed-meshheading:10660550-Arteriosclerosis,
pubmed-meshheading:10660550-Aryldialkylphosphatase,
pubmed-meshheading:10660550-Calcium,
pubmed-meshheading:10660550-Enzyme Inhibitors,
pubmed-meshheading:10660550-Esterases,
pubmed-meshheading:10660550-Homocysteine,
pubmed-meshheading:10660550-Humans,
pubmed-meshheading:10660550-Kinetics,
pubmed-meshheading:10660550-Lipoproteins, HDL,
pubmed-meshheading:10660550-Penicillamine,
pubmed-meshheading:10660550-Sequence Analysis,
pubmed-meshheading:10660550-Substrate Specificity
|
pubmed:year |
2000
|
pubmed:articleTitle |
Calcium-dependent human serum homocysteine thiolactone hydrolase. A protective mechanism against protein N-homocysteinylation.
|
pubmed:affiliation |
Department of Microbiology and Molecular Genetics, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, New Jersey 07103, USA. jakubows@umdnj.edu
|
pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, Non-P.H.S.
|