Linked Life Data

3334841

Source:http://linkedlifedata.com/resource/pubmed/id/3334841

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1988-2-11
pubmed:abstractText
A partially purified preparation of the aspartate/glutamate carrier from bovine heart mitochondria was reconstituted into liposomal membranes by chromatography on hydrophobic ion exchange resins. Based on the favorable conditions of this reconstituted system the transmembrane orientation of the inserted carrier protein could be determined by functional analysis. For reliable measurement of the reconstituted aspartate-glutamate exchange activity an optimized inhibitor-stop technique using pyridoxal phosphate was developed. By simultaneous application of both forward and backward exchange experiments the practical usefulness of the reconstituted system could be extended to investigations including variation of internal and external substrate concentrations over a wide range. Thereby a complete set of Km values for both aspartate and glutamate at both the internal and external side of the proteoliposomes could be established. These experiments led to the following results and conclusions: (i) The observed substrate affinities are clearly different for the two different membrane sides both for aspartate (external 50 microM, internal 3 mM) and glutamate (external about 200 microM, internal 3 mM). (ii) The exclusive presence of only one type of transport affinity for every single substrate at one side of the liposomal membrane clearly demonstrates the asymmetric orientation of the functionally active carrier protein molecules. (iii) When comparing the values of these constants with published data obtained in mitochondria, an inside-out orientation of the aspartate/glutamate carrier after isolation and reinsertion into liposomes is strongly suggested.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
13
pubmed:volume
937
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
112-26
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
Asymmetric orientation of the reconstituted aspartate/glutamate carrier from mitochondria.
pubmed:affiliation
Institut für Physikalische Biochemie, Universität München, F.R.G.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't