Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1985-8-9
pubmed:abstractText
The mammalian pyruvate dehydrogenase multi-enzyme complex contains a tightly-associated 50 000-Mr polypeptide of unknown function (component X) in addition to its three constituent enzymes, pyruvate dehydrogenase (E1), lipoate acetyltransferase (E2) and lipoamide dehydrogenase (E3) which are jointly responsible for production of CoASAc and NADH. The presence of component X is apparent on sodium dodecyl sulphate/polyacrylamide gel analysis of the complex, performed in Tris-glycine buffers although it co-migrates with the E3 subunit on standard phosphate gels run under denaturing conditions. Refined immunological techniques, employing subunit-specific antisera to individual components of the pyruvate dehydrogenase complex, have demonstrated that protein X is not a proteolytic fragment of E2 (or E3) as suggested previously. In addition, anti-X serum elicits no cross-reaction with either subunit of the intrinsic kinase of the pyruvate dehydrogenase complex. Immune-blotting analysis of SDS extracts of bovine, rat and pig cell lines and derived subcellular fractions have indicated that protein X is a normal cellular component with a specific mitochondrial location. It remains tightly-associated with the 'core' enzyme, E2, on dissociation of the complex at pH 9.5 or by treatment with 0.25 M MgCl2. This polypeptide is not released to any significant extent from E2 by p-hydroxymercuriphenyl sulphonate, a reagent which promotes dissociation of the specific kinase of the complex from the 'core' enzyme. Incubation of the complex with [2-14C]pyruvate in the absence of CoASH promotes the incorporation of radio-label, probably in the form of acetyl groups, into both E2 and component X.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0014-2956
pubmed:author
pubmed:issnType
Print
pubmed:day
18
pubmed:volume
149
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
641-8
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1985
pubmed:articleTitle
Component X. An immunologically distinct polypeptide associated with mammalian pyruvate dehydrogenase multi-enzyme complex.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't