Open AccessFrom identification of fluorescent flavoproteins to mitochondrial redox indicators in intact tissues
Author(s) -
Ilmo E. Hassinen
Publication year - 2014
Publication title -
journal of innovative optical health sciences/journal of innovation in optical health science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.421
H-Index - 24
eISSN - 1793-5458
pISSN - 1793-7205
DOI - 10.1142/s1793545813500582
Subject(s) - flavoprotein , nad+ kinase , flavin group , biochemistry , nicotinamide adenine dinucleotide , mitochondrion , redox , dehydrogenase , fluorescence , glycerol 3 phosphate dehydrogenase , flavin adenine dinucleotide , mitochondrial matrix , dihydrolipoamide dehydrogenase , biology , cytosol , chemistry , cofactor , enzyme , quantum mechanics , physics , organic chemistry
Development of the use of flavin and nicotinamide-adenine nucleotide fluorescence in monitoring the redox state of the free mitochondrial NADH/NAD+ couple in cells, tissues and organs is reviewed. A break-through was the identification of dihydrolipoamide dehydrogenase (FpL) as the major NAD-linked fluorescent flavoprotein of mitochondria. This mitochondrial matrix flavoprotein is in equilibrium with the free NADH/NAD+ pool and its mid-potential is sufficiently near to that of NADH/NAD+ so that its percentage reduction follows that of the latter. Possibilities of monitoring mitochondrial and cytosolic NADH depend on the population density of mitochondria and thus are tissue-dependent. Upon a shift toward reduction, fluorescence intensities of NADH and flavins swing to reciprocal directions, so that the NADH/flavin fluorescence ratio can be used to increase the sensitivity of redox monitoring. This method is attaining widening use in studies on metabolic regulation under normal and pathological conditions