: Life Sci 2001 May 4;68(24):2741-50Books

The reduction of NADH ubiquinone oxidoreductase 24- and 75-kDa subunits in brains of patients with Down syndrome and Alzheimer's disease.

Kim SH, Vlkolinsky R, Cairns N, Fountoulakis M, Lubec G.

Department of Pediatrics, University of Vienna, Austria.

NADH: ubiquinone oxidoreductase (complex I), one of the most complicated

multi-protein enzyme complexes, is important for energy metabolism because

it is the initial enzyme of the mitochondrial respiratory chain. Deficiency

of complex I is frequently found in various tissues of patients with

neurodegenerative disease. Here we studied the protein levels of complex I

24- and 75-kDa subunits in several brain regions from patients with Down

syndrome (DS) and Alzheimer's disease (AD). We determined protein levels of

complex I 24-, 75-kDa subunits and mitochondrial marker proteins

mitochondrial matrix protein P1 (hsp60) and aconitate hydratase from seven

brain regions of patients with DS, AD and controls. Proteins were separated

by two-dimensional (2-D) gel electrophoresis and identified by

matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS).

Complex I 24-kDa subunit was significantly reduced in occipital cortex and

thalamus in patients with DS and temporal and occipital cortices in

patients with AD. Complex I 75-kDa subunit was significantly reduced in

brain regions from patients with DS (temporal, occipital and caudate

nucleus) and AD (parietal cortex). Reductions of two subunits of complex I

may lead to the impairment of energy metabolism and result in neuronal cell

death (apoptosis), a hallmark of both neurodegenerative disorders.

PMID: 11400916 [PubMed - in process]