Linked Life Data

10725313

Source:http://linkedlifedata.com/resource/pubmed/id/10725313

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2000-5-1
pubmed:abstractText
N-Acetylation of xenobiotic-derived cysteine S-conjugates is a key step in the mercapturic acid pathway. The aim of this study was to investigate the N-acetylation of haloalkene-derived S-haloalkyl and S-haloalkenyl cysteine S-conjugates by porcine kidney cysteine S-conjugate N-acetyltransferase (NAcT). A radioactive assay for the quantification of NAcT activity was developed as a new method for partial purification of the enzyme, which was necessitated by the substantial loss of activity during the immunoaffinity chromatography method. 3-[(3-Cholamidopropyl)dimethylammonio]-1-propane-sulfonate, rather than N,N-bis[3-gluconamidopropyl]deoxycholamide, was used to solubilize the NAcT from porcine kidney microsomes in the revised procedure. The partially purified NAcT was free of detectable aminoacylase activity. Although low acetyl-coenzyme A hydrolase activity was observed, its effect on the assay was minimized by addition of excess acetyl-coenzyme A in the NAcT assay mixture. Attempts to separate the residual hydrolase activity from NAcT by different chromatographic procedures were either unsuccessful or lead to inactivation of NAcT. Most of the cysteine S-conjugates studied were N-acetylated by NAcT. Although the apparent K(m) values for the cysteine S-conjugates studied differed by a factor of approximately 2.5 (124-302 microM), a greater than 15-fold difference in the apparent V(max) (0.75-15.6 nmol/h) and V(max)/K(m) (0.008-0.126 x 10(-3) l h(-1)) values was observed. These data show that a range of haloalkene-derived cysteine S-conjugates serve as substrates for pig kidney NAcT. The significant differences in cytotoxicity of these conjugates may be a result of more variable deacetylation rates of the corresponding mercapturates.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0090-9556
pubmed:author
pubmed:issnType
Print
pubmed:volume
28
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
440-5
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Porcine kidney microsomal cysteine S-conjugate N-acetyltransferase-catalyzed N-acetylation of haloalkene-derived cysteine S-conjugates.
pubmed:affiliation
Institut für Biochemie, Technische Universität Darmstadt, Darmstadt, Germany.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't