Parallel measurement of oxoglutarate dehydrogenase activity and matrix free Ca super(2+) in fura-2-loaded heart mitochondria

The entrapment of the Ca super(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 super(2+) ((Ca super(2+)) sub(m)). In this paper the correlation between the (Ca super(2+)) sub(m) and...

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Bibliographic Details
Published in:FEBS letters 1988-01, Vol.229 (1), p.219-223
Main Authors: Lukacs, G L, Kapus, A, Fonyo, A
Format: Article
Language:English
Online Access:Get full text
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Summary:The entrapment of the Ca super(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 super(2+) ((Ca super(2+)) sub(m)). In this paper the correlation between the (Ca super(2+)) sub(m) and the in situ activity of oxoglutarate dehydrogenase (OGDH) in fura-2-loaded mitochondria is shown. At the initial value of (Ca super(2+)) sub(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 mu M (Ca super(2+)) sub(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 super(2+)) sub(m).
ISSN:0014-5793