Abstract
The composition and activity of cytochrome c oxidase (COX) was studied in mitochondria from rat liver, brain, kidney and heart and also in different compartments of the bovine heart to see whether any correlation exists between known oxidative capacity and COX activity. Immunoblot analysis showed that the levels of ubiquitously expressed subunits IV and Vb are about 8-12- fold lower in liver mitochondria as compared to the heart, kidney and brain. The heart enzyme with higher abundance of COX IV and Vb showed lower turnover number (495) while the liver enzyme with lower abundance of these subunits exhibited higher turnover number of 750. In support of the immunoblot results, immunohistochemical analysis of heart and kidney tissue sections showed an intense staining with the COX Vb antibody as compared to the liver sections. COX Vb antibody stained certain tubular regions of the kidney more intensely than the other regions suggesting region specific variation in the subunit level. Bovine heart compartments showed variation in subunit levels and also differed in the kinetic parameters of COX. The fight atrium contained relatively more Vb protein, while the left ventricle contained higher level of subunit VIa. COX from both the ventricles showed high K(m) for cytochrome c (23-37 μM) as compared to the atrial COX (K(m) 8-15 μM). These results suggest a correlation between tissue specific oxidative capacity/work load and changes in subunit composition and associated changes in the activity of COX complex. More important, our results suggest variations based on the oxidative load of cell types within a tissue.
| Original language | English |
|---|---|
| Pages (from-to) | 71-82 |
| Number of pages | 12 |
| Journal | BBA - Biomembranes |
| Volume | 1371 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - Apr 22 1998 |
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Keywords
- Cytochrome c oxidase
- Heart
- Kidney
- Kinetic property
- Mitochondrion
- Subunit content
ASJC Scopus subject areas
- Biochemistry
- Cell Biology
- Biophysics
Cite this
Variations in the subunit content and catalytic activity of the cytochrome c oxidase complex from different tissues and different cardiac compartments. / Vijayasarathy, C.; Biunno, Ida; Lenka, Nibedita; Yang, Ming; Basu, Aruna; Hall, Ian P.; Avadhani, Narayan G.
In: BBA - Biomembranes, Vol. 1371, No. 1, 22.04.1998, p. 71-82.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Variations in the subunit content and catalytic activity of the cytochrome c oxidase complex from different tissues and different cardiac compartments
AU - Vijayasarathy, C.
AU - Biunno, Ida
AU - Lenka, Nibedita
AU - Yang, Ming
AU - Basu, Aruna
AU - Hall, Ian P.
AU - Avadhani, Narayan G.
PY - 1998/4/22
Y1 - 1998/4/22
N2 - The composition and activity of cytochrome c oxidase (COX) was studied in mitochondria from rat liver, brain, kidney and heart and also in different compartments of the bovine heart to see whether any correlation exists between known oxidative capacity and COX activity. Immunoblot analysis showed that the levels of ubiquitously expressed subunits IV and Vb are about 8-12- fold lower in liver mitochondria as compared to the heart, kidney and brain. The heart enzyme with higher abundance of COX IV and Vb showed lower turnover number (495) while the liver enzyme with lower abundance of these subunits exhibited higher turnover number of 750. In support of the immunoblot results, immunohistochemical analysis of heart and kidney tissue sections showed an intense staining with the COX Vb antibody as compared to the liver sections. COX Vb antibody stained certain tubular regions of the kidney more intensely than the other regions suggesting region specific variation in the subunit level. Bovine heart compartments showed variation in subunit levels and also differed in the kinetic parameters of COX. The fight atrium contained relatively more Vb protein, while the left ventricle contained higher level of subunit VIa. COX from both the ventricles showed high K(m) for cytochrome c (23-37 μM) as compared to the atrial COX (K(m) 8-15 μM). These results suggest a correlation between tissue specific oxidative capacity/work load and changes in subunit composition and associated changes in the activity of COX complex. More important, our results suggest variations based on the oxidative load of cell types within a tissue.
AB - The composition and activity of cytochrome c oxidase (COX) was studied in mitochondria from rat liver, brain, kidney and heart and also in different compartments of the bovine heart to see whether any correlation exists between known oxidative capacity and COX activity. Immunoblot analysis showed that the levels of ubiquitously expressed subunits IV and Vb are about 8-12- fold lower in liver mitochondria as compared to the heart, kidney and brain. The heart enzyme with higher abundance of COX IV and Vb showed lower turnover number (495) while the liver enzyme with lower abundance of these subunits exhibited higher turnover number of 750. In support of the immunoblot results, immunohistochemical analysis of heart and kidney tissue sections showed an intense staining with the COX Vb antibody as compared to the liver sections. COX Vb antibody stained certain tubular regions of the kidney more intensely than the other regions suggesting region specific variation in the subunit level. Bovine heart compartments showed variation in subunit levels and also differed in the kinetic parameters of COX. The fight atrium contained relatively more Vb protein, while the left ventricle contained higher level of subunit VIa. COX from both the ventricles showed high K(m) for cytochrome c (23-37 μM) as compared to the atrial COX (K(m) 8-15 μM). These results suggest a correlation between tissue specific oxidative capacity/work load and changes in subunit composition and associated changes in the activity of COX complex. More important, our results suggest variations based on the oxidative load of cell types within a tissue.
KW - Cytochrome c oxidase
KW - Heart
KW - Kidney
KW - Kinetic property
KW - Mitochondrion
KW - Subunit content
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U2 - 10.1016/S0005-2736(97)00278-2
DO - 10.1016/S0005-2736(97)00278-2
M3 - Article
VL - 1371
SP - 71
EP - 82
JO - Biochimica et Biophysica Acta - Biomembranes
JF - Biochimica et Biophysica Acta - Biomembranes
SN - 0005-2736
IS - 1
ER -