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Parallel measurement of oxoglutarate dehydrogenase activity and matrix free Ca 2+ in fura‐2‐loaded heart mitochondria
Author(s) -
Lukács Gergely L.,
Kapus András,
Fonyó Attila
Publication year - 1988
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 - 10.1016/0014-5793(88)80831-7
Subject(s) - mitochondrion , dehydrogenase , chemistry , mitochondrial matrix , matrix (chemical analysis) , analytical chemistry (journal) , biophysics , biochemistry , enzyme , biology , chromatography , cytosol
The entrapment of the Ca 2+ ‐sensitive fluorescence indicators fura‐2 or quin2 in the matrix space of isolated heart mitochondria renders possible the direct monitoring of the matrix free Ca 2+ ([Ca 2+ ] m ) [(1987) Biochem. J. 248, 609–613]. In this paper the correlation between the [Ca 2+ ] m and the in situ activity of oxoglutarate dehydrogenase (OGDH) in fura‐2‐loaded mitochondria is shown. At the initial value of [Ca 2+ ] m , 64 nM, which corresponded to 0.36 nmol/mg mitochondrial Ca content, the OGDH activity was 12% of the maximal. Half‐maximal and maximal activation were attained at 0.8 and 1.6 μM [Ca 2+ ] m , respectively. The results indicate that an increase of the mitochondrial Ca content in the physiological range enhances the OGDH activity by means of elevation of [Ca 2+ ] m .