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. 1988 Nov;43(5):764–769.

Mitochondrial import and processing of an in vitro synthesized human prebranched chain acyltransferase fragment.

S Litwer 1, D J Danner 1
PMCID: PMC1715554  PMID: 3189339

Abstract

A 1.6-kb cDNA for human liver branched-chain acyltransferase [E2b] was placed in a transcription vector under the control of the SP6 promoter. In vitro translation of transcripts from this vector produced a pre-E2b fragment of Mr 39,000. Following import into mitochondria, this protein was processed to a protein with an Mr of 36,000. The processed protein was fully protected from trypsin digestion. Import and processing did not occur in the presence of rhodamine 123 or carbonyl cyanide m-chlorophenyl hydrazone, suggesting that membrane potential and coupled respiration were required. Uptake and processing were species and tissue independent, since both mouse-liver and human-lymphoblast mitochondria converted the human pre-E2b protein fragment. Mitochondria from patient cells that lack E2b through an inherited defect were able to import and process the in vitro-made protein, suggesting that the inherited defect was in the gene for E2b and not in the organelle-structure function. This system now provides additional methods for investigation of mechanisms responsible for the human inherited disorders affecting the branched-chain alpha-ketoacid dehydrogenase complex.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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