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Microinjected glutathione reductase crystals as indicators of the redox status in living cells
Author(s) -
Keese Michael A.,
Saffrich Rainer,
Dandekar Thomas,
Becker Katja,
Schirmer R.Heiner
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)00296-3
Subject(s) - glutathione , redox , glutaredoxin , intracellular , glutathione reductase , chemistry , cytosol , glutathione disulfide , electron transfer , biochemistry , biophysics , reductase , enzyme , photochemistry , biology , glutathione peroxidase , inorganic chemistry
The flavoenzyme glutathione reductase catalyses electron transfer reactions between two major intracellular redox buffers, namely the NADPH/NADP + couple and the 2 glutathione/glutathione disulfide couple. On this account, microcrystals of the enzyme were tested as redox probes of intracellular compartments. For introducing protein crystals into human fibroblasts, different methods (microinjection, particle bombardment and optical tweezers) were explored and compared. When glutathione reductase crystals are present in a cytosolic environment, the transition of the yellow E ox form to the orange‐red 2‐electron reduced charge transfer form, EH 2 , is observed. Taking into account the midpoint potential of the E ox /EH 2 couple, the redox potential of the cytosol was found to be <−270 mV at pH 7.4 and 37°C. As a general conclusion, competent proteins in crystalline – that is signal‐amplifying – form are promising probes for studying intracellular events.