Molecular and Cellular Biochemistry

, Volume 174, Issue 1, pp 329–333

Mitochondrial Complex I defects in aging

  • Giorgio Lenaz
  • Carla Bovina
  • Cinzia Castelluccio
  • Romana Fato
  • Gabriella Formiggini
  • Maria Luisa Genova
  • Mario Marchetti
  • Milena Merlo Pich
  • Francesco Pallotti
  • Giovanna Parenti Castelli
  • Graziella Biagini
Article

DOI: 10.1023/A:1006854619336

Cite this article as:
Lenaz, G., Bovina, C., Castelluccio, C. et al. Mol Cell Biochem (1997) 174: 329. doi:10.1023/A:1006854619336

Abstract

According to the 'mitochondrial theory of aging' it is expected that the activity of NADH Coenzyme Q reductase (Complex I) would be most severely affected among mitochondrial enzymes, since mitochondrial DNA encodes for 7 subunits of this enzyme. Being these subunits the site of binding of the acceptor substrate (Coenzyme Q) and of most inhibitors of the enzyme, it is also expected that subtle kinetic changes of quinone affinity and enzyme inhibition could develop in aging before an overall loss of activity would be observed.

The overall activity of Complex I was decreased in several tissues from aged rats, nevertheless it was found that direct assay of Complex I using artificial quinone acceptors may underevaluate the enzyme activity. The most acceptable results could be obtained by applying the 'pool equation' to calculate Complex I activity from aerobic NADH oxidation; using this method it was found that the decrease in Complex I activity in mitochondria from old animals was greater than the activity calculated by direct assay of NADH Coenzyme Q reductase.

A decrease of NADH oxidation and its rotenone sensitivity was observed in nonsynaptic mitochondria, but not in synaptic 'light' and 'heavy' mitochondria of brain cortex from aged rats.

In a study of Complex I activity in human platelet membranes we found that the enzyme activity was unchanged but the titre for half-inhibition by rotenone was significantly increased in aged individuals and proposed this change as a suitable biomarker of aging and age-related diseases. (Mol Cell Biochem 174: 329–333, 1997)

ageingplatelet mitochondrionComplex Irotenone sensitivity

Copyright information

© Kluwer Academic Publishers 1997

Authors and Affiliations

  • Giorgio Lenaz
    • 1
  • Carla Bovina
    • 1
  • Cinzia Castelluccio
    • 1
  • Romana Fato
    • 1
  • Gabriella Formiggini
    • 1
  • Maria Luisa Genova
    • 1
  • Mario Marchetti
    • 1
  • Milena Merlo Pich
    • 1
  • Francesco Pallotti
    • 2
  • Giovanna Parenti Castelli
    • 1
  • Graziella Biagini
    • 3
  1. 1.Dipartimento di Biochimica 'G. Moruzzi'University of BolognaBolognaItaly
  2. 2.Istituto di IstologiaUniversity of BolognaBolognaItaly
  3. 3.Istituto di MorfologiaUniversity of AnconaAnconaItaly