Bernhard Kadenbach

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Bernhard Kadenbach (2010)

Bernhard Kadenbach (born August 21, 1933 in Luckenwalde ; † April 14, 2021 in Marburg ) was a German biochemist with a research focus on the structure and function of mitochondrial cytochrome c oxidase , who was a professor in the chemistry department at the Philipps University of Marburg .

Life

academic career

Bernhard Kadenbach was born in Luckenwalde as the fifth of eight children of the commercial teacher Bernhard Kadenbach and his wife Elfriede (née Brix). After graduating from the Gerhart Hauptmann School in Luckenwalde in 1952, Kadenbach studied chemistry at the Humboldt University in Berlin from 1952 - at that time Robert Havemann was dean of the natural sciences faculty and director of the institute for physical chemistry . Kadenbach graduated with a diploma in 1959 . The diploma thesis under the supervision of the organic scientist Otto Neunhoeffer took place in the Robert-Rössle-Krebs-Klinik of the Academy of Sciences of the GDR (DAdW) in Berlin-Buch , at that time one of the most renowned biomedical research clinics of the Eastern Bloc countries .

From 1959 to 1961, Kadenbach worked in the same position as a research assistant. During this time he completed a one-year research stay in the laboratory of Lars Ernster and Olaf Lindberg at the Wenner-Gren Institute of Stockholm University in 1960 . Kadenbach returned to East Berlin in December 1960. Since Otto Neunhoeffer had left Berlin in 1960 to go to the West at Saarland University , Saarbrücken, Kadenbach began his doctoral thesis under Samuel Mitja Rapoport . At the end of August 1961, Kadenbach finally left the GDR with false papers.

In 1961 he worked as an assistant to Theodor Bücher at the Institute for Physiological Chemistry at the Philipps University of Marburg , which Kadenbach completed with a doctorate in 1964 , which was followed by a DFG research grant until 1968 in the same position. From 1969 to 1971 he was a research assistant at the chair for physical biochemistry at the Ludwig Maximilians University in Munich with Martin Klingenberg , who had also worked on mitochondria for Theodor Bücher in Marburg, and whose interest was the ADP - ATP - transporter .

Biomedical Research Center (BMFZ)

Kadenbach completed his habilitation in 1970 at the University of Konstanz and worked from 1971 to 1973 as senior assistant and lecturer in the laboratory for biochemistry at the Swiss Federal Institute of Technology in Zurich with Carl Martius .

In October 1973, Kadenbach was appointed to a professorship for biochemistry in the chemistry department of the Philipps University of Marburg, which he held until his retirement in 1998.

From 2001 to 2011, as an active scientist in DFG-funded projects, Kadenbach supervised two doctoral students at the Biomedical Research Center (BMFZ) at the Clinic of the Philipps University in Marburg and ensured the support of technical staff in the cardiac surgery laboratory.

Research areas

From 1973 to 2010, 76 diploma theses in chemistry / biochemistry were written under the direction of Kadenbach, and 45 doctoral students completed their doctorates (dissertations by research area): 31 thematically on cytochrome c oxidase, seven on mitochondrial myopathies , four on mitochondrial Phosphate transport and three on biochemical and biomedical methodology and analysis .

Mitochondrial Phosphate Transport

Mitochondrion (schematic representation). Cytochrome c oxidase and phosphate transport protein are inner membrane transmembrane proteins.

From 1973 to 1982, when neither the gene nor the amino acid sequence of the mitochondrial phosphate transport protein was known, Kadenbach and co-workers investigated phosphate binding of mitochondrial extracts and phosphate uptake in isolated mitochondria. In the latter case, the competitive inhibition of transport with reversible sulfhydryl reagents ( organic mercury compounds such as mersalyl and salts of ethyl mercurithiosalicylic acid ) and the irreversible SH inhibitor N-ethylmaleimide was investigated on the one hand to determine the specificity of the phosphate transporter compared to the dicarboxylate transporter another member of the mitochondrial carrier family , and on the other hand to determine the substrate specificity of this transmembrane protein.

To purify the phosphate transporter, fractions of mitochondrial membranes were solubilized by non-ionic detergents and partially purified using hydroxyapatite and other stationary phases until protein-analytical identification of the phosphate transporter by SDS-PAGE was possible (M r around 32 kDa ). Reconstitution of the purified phosphate transporter in liposomes showed specifically inhibitable phosphate transport, which showed a stimulated activity in the presence of cardiolipin , which occurs naturally in mitochondria .

Cytochrome c oxidase (COX)

Expression

Using cytochrome c as an example, Kadenbach investigated the cytoplasmic biosynthesis of mitochondrial proteins as early as the late 1960s. He showed that some subunits of cytochrome c oxidase (COX) are synthesized cytosolic and others mitochondrially (i.e. inside the mitochondria).

Subunits and cDNAs
Mitochondrial genome (schematic representation)
Cytochrome c oxidase homodimer (alignment of the enzyme complex with its 13 subunits in the mitochondrial membrane in the ribbon model)

In 1983, Kadenbach and co-workers demonstrated by protein analysis that COX protein complexes purified from mitochondria from different mammals each consist of 13 individual subunits . This large number of distinguishable subunits has long not been recognized by mitochondriologists and has been hotly debated. It was not until 13 years later that the final proof came through the elucidation of the crystal structure of the COX multimer by Yoshikawa and co-workers, which made the position of the 13 proteins in relation to one another visible.

Although COX complexes have the same enzymatic function in bacteria and mammals, bacterial COX complexes contain only 3 subunits. Regulatory functions have been demonstrated for some of the 10 additional subunits in the mammal. Polyclonal and monoclonal antibodies were produced in Marburg against each of the 13 subunits of the COX . Tissue-specific isoforms of the COX subunits VIa, VIIa, and VIII were described for the first time, and differences in the kinetic activity of the COX isolated from different organs were shown. The variable expression of COX isoenzymes has also been demonstrated immunohistochemically in various human muscle fibers .

The genes ( cDNAs ) for the two (heart and liver) isoforms of subunit VIa and for further subunits were isolated and sequenced and the chromosomal gene structures for subunits VIc and VIa were determined. The development- specific ( fetal / adult ) expression of the isoforms could also be demonstrated in human tissue .

Kinetics and Regulation

Binding studies by Kadenbach and co-workers showed 10 high-affinity ADP binding sites on isolated COX from bovine heart . These 10 ADP binding sites were confirmed in the crystal structure by the incorporation of 10 cholate molecules (similar spatial structure). Measurements of the stoichiometry of the proton transport of the isolated COX reconstituted in liposomes confirmed a functional regulation by the ADP / ATP ratio.

Another allosteric mechanism of respiratory control through the ATP / ADP ratio was found through binding specifically to subunit IV. Work between 2000 and 2011 finally led Kadenbach to formulate a hypothesis regarding the role of COX regulation with regard to the aging process and the development of degenerative diseases in humans and animals.

Mitochondrial myopathies

The antibodies against the COX subunits produced in Kadenbach's work group were used for the immunohistochemical detection of mitochondrial myopathies with COX defects. In collaboration with Josef Müller-Höcker, it was possible for the first time to demonstrate the increase in COX-defective cells in the muscles and in the liver of healthy people with increasing age.

Using the “mispairing PCR ” method , point mutations were identified in samples from patients with MERRF syndrome and proven to be a common cause of various neuromuscular diseases. In addition, two different detection methods were used to find that the point mutations characteristic of MERRF increase with increasing age, even in healthy test subjects.

It has been postulated that the lifespan of humans is also limited by the fact that statistical mutations of the mitochondrial DNA (mtDNA), which accumulate with increasing age, result in COX-deficient cells.

Philosophical Aspects of Science

In 2016 Kadenbach published the book Why does man live and where does evil come from? Thoughts and Views of a Natural Scientist .

Memberships

Publications

  • 1959 ( Diploma ) The influence of chlorpromazine on the oxidative phosphorylation of tumor mitochondria
  • 1964 ( dissertation ) The influence of thyroid hormones in vivo on oxidative phosphorylation and enzyme activities in mitochondria
  • 1970 ( Habilitation ) The biosynthesis of cytochrome c

From 1959 to 2012 Kadenbach published 237 articles in national and international journals. The following publications deserve special mention:

  • P. Merle and B. Kadenbach: The subunit composition of mammalian cytochrome c oxidase , Eur J Biochem 105, 499-507 (1980).
  • B. Kadenbach, P. Mende, HVJ Kolbe, I. Stipani and F. Palmieri: The mitochondrial phosphate carrier has an essential requirement for cardiolipin , FEBS Lett . 139: 109-112 (1982).
  • B. Kadenbach, C. Münscher, V. Frank, J. Müller-Höcker and J. Napiwotzki: Human aging is associated with stochastic somatic mutations of mitochondrial DNA , Mutation Res. 338, 161-172 (1995).
  • B. Kadenbach (Ed.): Mitochondrial Oxidative Phosphorylation. Nuclear-Encodes Genes, Enzyme Regulation, and Pathophysiology ( Advances in Medical Medicine and Biology 748), Springer-Verlag (2012) ISBN 9781461435723 .
  • B. Kadenbach: The human being, an electrical being , chemistry in our time 49, 2-7 (2015).
  • B. Kadenbach and M. Hüttemann: The subunit composition and function of mammalian cytochrome c oxidase , Mitochondrion 24, 64-76 (2015).

literature

Web links

Individual evidence

  1. ↑ Ernst Peter Fischer: The Charité: A hospital in Berlin - 1710 until today , Siedler Verlag (2010), p. 2 f.
  2. ↑ P. Hadvary and B. Kadenbach: Identification of a membrane protein involved in mitochondrial phosphate transport , Eur. J. Biochem. 65: 573-581 (1976).
  3. ↑ H. Freitag and B. Kadenbach Inhibition of malate transport and activation of phosphate transport in mitochondria by ethylmercurithiosalicylate , FEBS Lett. 117: 149-151 (1980).
  4. ↑ H. Freitag and B. Kadenbach: Transport of phosphate analogues in rat liver mitochondria , Eur. J. Biochem. 83: 53-57 (1978).
  5. ↑ HVJ Kolbe, P. Mende and B. Kadenbach: The protein component (s) of the isolated phosphate-transport system of mitochondria , Eur. J. Biochem. 128: 97-105 (1982).
  6. ↑ P. Mende, HVJ Kolbe, B. Kadenbach, I. Stipani, and F. Palmieri: Reconstitution of the isolated phosphate transport system of pig-heart mitochondria ., Eur J. Biochem. 128: 91-95 (1982).
  7. ↑ P. Mende, F.-J. Hüther and B. Kadenbach: Specific and reversible activation and inactivation of the mitochondrial phosphate carrier by cardiolipin and nonionic detergents, respectively , FEBS Lett. 158: 331-334 (1983).
  8. ↑ B. Kadenbach: Biosynthesis of cytochrome c. The sites of synthesis of apoprotein and holoenzyme , Eur. J. Biochem. , 12: 392-398 (1970).
  9. ↑ B. Kadenbach: Synthesis of mitochondrial proteins. Demonstration of a transfer of proteins from microsomes into mitochondria , Biochim. Biophys. Acta 134: 430-443 (1967).
  10. ↑ Lecture at the meeting "Autonomy and Biogenesis of Mitochondria and Chloroplasts" from December 8th to 13th, 1969 in Canberra, Australia and published under B. Kadenbach: Biosynthesis of mitochondrial cytochromes , in: "Autonomy and biogenesis of mitochondria and chloroplasts" ( NK Boardman, AW Linnane and RM Smillie, eds.), North-Holland, Amsterdam, London, pp. 360-371 (1971).
  11. ↑ B. Kadenbach, J. Jarausch, R. Hartmann and P. Merle: Separation of mammalian cytochrome c oxidase into 13 poly-peptides by a sodium dodecyl sulfate-gel electrophoretic procedure , Anal. Biochem. 129: 517-521 (1983).
  12. ↑ B. Kadenbach, M. Ungibauer, J. Jarausch, U. Büge and L. Kuhn-Nentwig: The complexity of respiratory complexes , Trends Biochem. Sci. 8: 398-400 (1983).
  13. ↑ T. Tsukihara, H. Aoyama, E. Yamashita, T. Tomizaki, H. Yamaguchi, K. Shinzawa-Itoh, R. Nakashima, R. Yaono and S. Yoshikawa: The whole structure of the 13-subunit oxidized cytochrome c oxidase at 2.8 A, Science . 272: 1136-1144 (1996).
  14. ↑ The subunits I to III, which are analogous to bacteria, are encoded by mitochondrial DNA and synthesized in the organelle (see also endosymbiont theory ). The biosynthesis of the additional 10 subunits in mammals takes place in the cytosol .
  15. ↑ On request, the monoclonal antibodies against the individual COX subunits from bovine heart mitochondria were sent worldwide as specific detection reagents.
  16. ↑ B. Kadenbach, R. Hartmann, R. Glanville and G. Buse: Tissue-specific genes code for polypeptide VIa of beef liver and heart cytochrome c oxidase , FEBS Lett. 138: 236-238 (1982).
  17. ↑ P. Merle and B. Kadenbach: Kinetic and structural differences between cytochrome c oxidases from beef liver and heart , Eur. J. Biochem. 125: 239-244 (1982).
  18. ↑ N. Romero, C. Marsac, M. Fardeau, M. Droste, B. Schneyder and B. Kadenbach: Immunohistochemical demonstration of fiber type-specific isozymes of cytochrome c oxidase in human skeletal muscle histochemistry 94, 211-215 (1990) .
  19. ↑ A. Schlerf, M. Droste, M. Winter and B. Kadenbach: Characterization of two different genes (cDNA) for cytochrome c oxidase subunit VIa from heart and liver of the rat , EMBO J. 7, 2387-2391 (1988) .
  20. ↑ Subunits VIc and VIII from hepatoma cells (rat), Va (heart, rat), IV (fetal liver, rat), VIa (human liver), VIIa (liver, rat), and VIII (heart, rat)
  21. ^ O. Mell, P. Seibel and B. Kadenbach: Structural organization of the rat genes encoding liver- and heart-type of cytochrome c oxidase subunit VIa and a pseudogene related to the COXVIa-L cDNA , Gene 140, 179-186 ( 1994).
  22. ↑ Analyzes were carried out with Northern blots (cDNA detection) and Western blots (immunological protein detection).
  23. ↑ G. Bonne, P. Seibel, S. Possekel, C. Marsac and B. Kadenbach: Expression of human cytochrome c oxidase subunits during fetal development , Eur. J. Biochem. 217, 1099-1107 (1993).
  24. ↑ The occupation of these binding sites with ADP depends on the ATP / ADP ratio. If the ATP / ADP ratio is high, ADP is exchanged for ATP.
  25. ^ A b J. Napiwotzki, K. Shinzawa-Itoh, S. Yoshikawa and B. Kadenbach: ATP and ADP bind to cytochrome c oxidase and regulate its activity , Biol. Chem., 378, 1013-1021 (1997).
  26. ↑ B. Ludwig, E. Bender, S. Arnold, M. Hüttemann, I. Lee and B. Kadenbach Cytochrome c oxidase and the regulation of oxidative phosphorylation ( Memento of the original from June 26, 2015 in the Internet Archive ) Info: The archive link was used automatically and has not yet been tested. Please check the original and archive link according to the instructions and then remove this notice. , ChemBioChem 2, 392-403 (2001). @1@ 2Template: Webachiv / IABot / web.uni-frankfurt.de
  27. ↑ In the case of bovine heart enzyme (heart type), a reduction in the H + / e - stoichiometry from 1.0 to 0.5 was found with a high ATP / ADP ratio (binding to subunit VIa)
  28. ^ V. Frank and B. Kadenbach: Regulation of the H + / e - stoichiometry of cytochrome c oxidase from bovine heart by intraliposomal ATP / ADP ratios , FEBS Lett., 382, ​​121-124 (1996).
  29. ↑ This mechanism is based on the allosteric inhibition of COX at a high ATP / ADP ratio: d. H. the polarographic measurement of the oxygen consumption with increasing cytochrome c concentration shows a sigmoidal inhibition curve. This mechanism is abolished (a) with a low ATP / ADP ratio, (b) by binding of 3,5-diiodothyronine (T2) to subunit Va, (c) by expression of isoform IV-2 (M. Hüttemann, B. . Kadenbach and LI Grossman: Mammalian subunit IV isoforms of cytochrome c oxidase , Gene 267, 111-123 (2001)) and (d) by dephosphorylation of the COX (I. Lee, E. Bender, S. Arnold and B. Kadenbach: Minireview-Hypothesis. New control of mitochondrial membrane potential and ROS formation , Biol. Chem. 382, ​​1629-1633 (2001)).
  30. ^ S. Arnold and B. Kadenbach: Priority Paper. Cell respiration is controlled by ATP, an allosteric inhibitor of cytochrome c oxidase , Eur. J. Biochem. 249: 350-354 (1997).
  31. ^ B. Kadenbach and S. Arnold: Minireview. A second mechanism of respiratory control , FEBS Lett. 447: 131-134 (1999).
  32. ↑ B. Kadenbach, R. Ramzan, L. Wen and Vogt: New extension of the Mitchell Theory for oxidative phosphorylation in mitochondria of living organisms , Biochim. Biophys. Acta 1800: 205-212 (2010).
  33. ↑ B. Kadenbach, R. Ramzan and S. Vogt: High efficiency versus maximal performance - The cause of oxidative stress in eukaryotes: A hypothesis , Mitochondrion 13 (2013) pp. 1-6
  34. ↑ L. Kuhn-Nentwig and B. Kadenbach: Isolation and properties of cytochrome c oxidase from rat liver and quantification of immunological differences between isozymes from various rat tissues with subunit-specific antisera Eur. J. Biochem. 149: 147-158 (1985).
  35. ↑ Pathologist at the Ludwig Maximilians University in Munich , specializing in: COX deficiency in biopsies of Kearns-Sayre syndrome patients; Tissue- and subunit-specific defects of the COX in autopsy material from infants
  36. ↑ J. Müller-Höcker, K. Schneiderbanger, FH Stefani and B. Kadenbach: Progressive loss of cytochrome-c-oxidase in the human extraocular muscles in aging - a cytochemical-immunohistochemical study , Mutation Research 275, 115-124 (1992) .
  37. ↑ P. Seibel, F. Degoul, N. Romero, C. Marsac and B. Kadenbach: Identification of point mutations by mispairing PCR as exemplified in MERRF disease , Biochem. Biophys. Res. Commun. 173: 561-565 (1990).
  38. ↑ C. Münscher, T. Rieger, J. Müller-Höcker and B. Kadenbach: The point mutation of mitochondrial DNA characteristic for MERRF disease is also found in healthy people of different age , FEBS Lett., 317, 27-30 (1993 ).
  39. ↑ No mutations in the mtDNA in under 20-year-olds, 2% in a 74-year-old, 2.4% in an 89-year-old test person.
  40. ↑ B. Kadenbach and J. Müller-Höcker: Mutations of mitochondrial DNA and human death , Naturwissenschaften 77, 221-225 (1990).
  41. ↑ B. Kadenbach: Why do humans live and where does evil come from? Thoughts and views of a natural scientist , Novum-Verlag (2016), ISBN 978-3-95840-054-2 .
personal data
SURNAME Kadenbach, Bernhard
BRIEF DESCRIPTION German biochemist
DATE OF BIRTH August 21, 1933
PLACE OF BIRTH Luckenwalde
DATE OF DEATH April 14, 2021
PLACE OF DEATH Marburg