Linked Life Data

3343250

Source:http://linkedlifedata.com/resource/pubmed/id/3343250

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
1988-4-6
pubmed:abstractText
The submitochondrial localization and identity of enzymes which metabolize cysteine conjugates were investigated. Glutamine transaminase K was purified from rat kidney mitochondrial soluble fraction and was shown to be a cysteine conjugate beta-lyase. The purified mitochondrial enzyme is similar to the cytosolic glutamine transaminase K whose beta-lyase activity with S-(1,2-dichlorovinyl)-L-cysteine (DCVC) is regulated by concurrent transamination (Stevens, J. L., Robbins, J. D., and Byrd, R. A. (1986) J. Biol. Chem. 261, 15529-15537). However, beta-lyase activity in whole mitochondria is largely independent of regulation by cosubstrates for transamination suggesting that factors present in mitochondria are able to support the beta-lyase activity in the absence of added alpha-keto acid. Fractionation of mitochondria results in a loss of the independent beta-lyase activity. However, the majority of the beta-lyase activity can be recovered in the matrix if it is stimulated by the addition of alpha-keto-gamma-methiolbutyrate. The data suggest that the regulation of beta-elimination by the competing transamination pathway is different for each substrate and that multiple beta-lyases may exist in rat kidney. S-(2-Benzothiazolyl)-L-cysteine (BTC) is a poor substrate for purified glutamine transaminase K from mitochondria and cytosol, but BTC is as active as DCVC in crude mitochondrial matrix suggesting that other enzymes may be present. In contrast to DCVC, with BTC as substrate, the beta-lyase activity of the purified enzyme and enzyme(s) in the mitochondrial matrix is largely alpha-keto acid-independent. The existence of multiple enzymes is also supported by the observation that alpha-keto acids which are not substrates for purified glutamine transaminase K from mitochondria and cytosol do stimulate beta-lyase activity in the mitochondrial matrix fraction. Mitoplasts were found to be sensitive to DCVC toxicity consistent with the matrix localization of beta-lyase activity. The possible role in cysteine conjugate toxicity of matrix enzyme regulation by alpha-keto acids is discussed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/2-keto-4-methylthiobutyric acid, http://linkedlifedata.com/resource/pubmed/chemical/Aminooxyacetic Acid, http://linkedlifedata.com/resource/pubmed/chemical/Benzothiazoles, http://linkedlifedata.com/resource/pubmed/chemical/Cysteine, http://linkedlifedata.com/resource/pubmed/chemical/Keto Acids, http://linkedlifedata.com/resource/pubmed/chemical/Lyases, http://linkedlifedata.com/resource/pubmed/chemical/Methionine, http://linkedlifedata.com/resource/pubmed/chemical/S-(1,2-dichlorovinyl)cysteine, http://linkedlifedata.com/resource/pubmed/chemical/S-(2-benzothiazolyl)cysteine, http://linkedlifedata.com/resource/pubmed/chemical/Transaminases, http://linkedlifedata.com/resource/pubmed/chemical/glutamine - phenylpyruvate..., http://linkedlifedata.com/resource/pubmed/chemical/kynurenine-oxoglutarate transaminase
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
263
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3395-401
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
The role of mitochondrial matrix enzymes in the metabolism and toxicity of cysteine conjugates.
pubmed:affiliation
W. Alton Jones Cell Science Center, Inc., Lake Placid, New York 12946.
pubmed:publicationType
Journal Article, Comparative Study