Carnitine acetyltransferase in pea cotyledon mitochondria

✍ Scribed by N. Burgess; D. R. Thomas

• Book ID: 104777599
• Publisher: Springer-Verlag
• Year: 1986
• Tongue: English
• Weight: 802 KB
• Volume: 167
• Category: Article
• ISSN: 0032-0935
• DOI: 10.1007/bf00446369

✦ Synopsis

Purified pea cotyledon mitochondria did not oxidise acetyl-CoA in the presence of carnitine. However, acetylcarnitine was oxidised. It was concluded that acetylcarnitine passed through the mitochondrial membrane barrier but acetyl-CoA did not. Only a sensitive radioactive assay detected carnitine acetyltransferase in intact mitochondrion or intact mitoplast preparations. When the mitochondria or mitoplasts were burst, acetyl-CoA substrate was available to the matrix carnitine acetyltransferase and a high activity of the enzyme was measured. The inner mitochondrial membrane is therefore the membrane barrier to acetyl-CoA but acetylcarnitine is suggested to be transported through this membrane via an integral carnitine: acylcarnifine translocator. Evidence is presented to indicate that when the cotyledons from 48-h-grown peas are oxidising pyruvate, acetylcarnitine formed in the mitochondrial matrix by the action of matrix carnitine acetyltransferase may be transported to extra-mitochondrial sites via the membrane translocator.