Affinity purification of cytochrome c reductase from potato mitochondria

authored by: Hans‐Peter Braun, Udo Schmitz
Abstract: Ubiquinol‐cytochrome‐c oxidoreductase has been isolated from potato (Solanum tuberosum L.) mitochondria by cytochrome‐c affinity chromatography and gel‐filtration chromatography. The procedure, which up to now only proved applicable to Neurospora, yields a highly pure and active protein complex in monodisperse state. The molecular mass of the purified complex is about 650 kDa, indicating that potato cytochrome c reductase occurs as a dimer. Upon reconstitution into phospholipid membranes, the dimeric enzyme catalyzes electron transfer from a synthetic ubiquinol to equine cytochrome c with a turnover number of 50 s⁻¹. The activity is inhibited by antimycin A and myxothiazol. A myxothiazol‐insensitive and antimycin‐sensitive transhydrogenation reaction, with a turnover number of 16 s⁻¹, can be demonstrated as well. The protein complex consists of ten subunits, most of which have molecular masses similar to those of the nine‐subunit fungal enzyme. Individual subunits were identified immunologically and spectral properties of b and c cytochromes were monitored. Interestingly, an additional ‘core’ polypeptide which is not present in other cytochrome bc₁ complexes forms part of the enzyme from potato. Antibodies raised against individual polypeptides reveal that the core proteins are clearly immuno‐distinguishable. The additional subunit may perform a specific function and contribute to the high molecular mass which exceeds those reported for other cytochrome‐c‐reductase dimers.
External Organisation(s): Max Planck Institute of Molecular Plant Physiology (MPI-MP)
Type: Article
Journal: European Journal of Biochemistry
Volume: 208
Pages: 761-767
No. of pages: 7
ISSN: 0014-2956
Publication date: 09.1992
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Biochemistry
Electronic version(s): https://doi.org/10.1111/j.1432-1033.1992.tb17245.x (Access: Unknown)

BibTeX

@article{47b3161e7c3a48b684494887a625d925,
title = "Affinity purification of cytochrome c reductase from potato mitochondria",
abstract = "Ubiquinol‐cytochrome‐c oxidoreductase has been isolated from potato (Solanum tuberosum L.) mitochondria by cytochrome‐c affinity chromatography and gel‐filtration chromatography. The procedure, which up to now only proved applicable to Neurospora, yields a highly pure and active protein complex in monodisperse state. The molecular mass of the purified complex is about 650 kDa, indicating that potato cytochrome c reductase occurs as a dimer. Upon reconstitution into phospholipid membranes, the dimeric enzyme catalyzes electron transfer from a synthetic ubiquinol to equine cytochrome c with a turnover number of 50 s−1. The activity is inhibited by antimycin A and myxothiazol. A myxothiazol‐insensitive and antimycin‐sensitive transhydrogenation reaction, with a turnover number of 16 s−1, can be demonstrated as well. The protein complex consists of ten subunits, most of which have molecular masses similar to those of the nine‐subunit fungal enzyme. Individual subunits were identified immunologically and spectral properties of b and c cytochromes were monitored. Interestingly, an additional {\textquoteleft}core{\textquoteright} polypeptide which is not present in other cytochrome bc1 complexes forms part of the enzyme from potato. Antibodies raised against individual polypeptides reveal that the core proteins are clearly immuno‐distinguishable. The additional subunit may perform a specific function and contribute to the high molecular mass which exceeds those reported for other cytochrome‐c‐reductase dimers.",
author = "Hans‐Peter Braun and Udo Schmitz",
year = "1992",
month = sep,
doi = "10.1111/j.1432-1033.1992.tb17245.x",
language = "English",
volume = "208",
pages = "761--767",
journal = "European Journal of Biochemistry",
issn = "0014-2956",
publisher = "Wiley-Blackwell Publishing Ltd",
number = "3",
}