HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: M800137-MCP200v1 7/9/1714    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Glossary Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Helling, S. Articles by Kadenbach, B. Search for Related Content PubMed PubMed Citation Articles by Helling, S. Articles by Kadenbach, B. Social Bookmarking                      What's this?

Molecular & Cellular Proteomics 7:1714-1724, 2008.
© 2008 by The American Society for Biochemistry and Molecular Biology, Inc.

---

Research

Phosphorylation and Kinetics of Mammalian Cytochrome c Oxidase^*

Stefan Helling, Sebastian Vogt, Annika Rhiel, Rabia Ramzan^¶, Li Wen^¶, Katrin Marcus^,|| and Bernhard Kadenbach^||,**

From the Medizinisches Proteom-Center, Funktionelle Proteomik, Ruhr-Universität Bochum, Biomedizinisches Forschungszentrum, and ^¶ Fachbereich Chemie, Philipps-University, D-35032 Marburg, Germany

The influence of protein phosphorylation on the kinetics of cytochrome c oxidase was investigated by applying Western blotting, mass spectrometry, and kinetic measurements with an oxygen electrode. The isolated enzyme from bovine heart exhibited serine, threonine, and/or tyrosine phosphorylation in various subunits, except subunit I, by using phosphoamino acid-specific antibodies. The kinetics revealed slight inhibition of oxygen uptake in the presence of ATP, as compared with the presence of ADP. Mass spectrometry identified the phosphorylation of Ser-34 at subunit IV and Ser-4 and Thr-35 at subunit Va. Incubation of the isolated enzyme with protein kinase A, cAMP, and ATP resulted in serine and threonine phosphorylation of subunit I, which was correlated with sigmoidal inhibition kinetics in the presence of ATP. This allosteric ATP-inhibition of cytochrome c oxidase was also found in rat heart mitochondria, which had been rapidly prepared in the presence of protein phosphatase inhibitors. The isolated rat heart enzyme, prepared from the mitochondria by blue native gel electrophoresis, showed serine, threonine, and tyrosine phosphorylation of subunit I. It is concluded that the allosteric ATP-inhibition of cytochrome c oxidase, previously suggested to keep the mitochondrial membrane potential and thus the reactive oxygen species production in cells at low levels, occurs in living cells and is based on phosphorylation of cytochrome c oxidase subunit I.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?