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Requirement for coenzyme Q in plasma membrane electron transport
1Department of Biological Sciences, Purdue University, West Lafayette, IN 47907.
Summary
Coenzyme Q is essential for plasma membrane electron transport, supporting cell growth. Its removal impairs NADH dehydrogenase activity, but restoration is possible with coenzyme Q addition.
Area of Science:
- Biochemistry
- Cell Biology
- Molecular Biology
Background:
- Coenzyme Q (CoQ) plays a vital role in cellular respiration.
- Its function in trans-plasma membrane electron transport (TPMET) is not fully understood.
Purpose of the Study:
- To investigate the role of CoQ in TPMET.
- To determine the effect of CoQ on cell growth.
Main Methods:
- Extraction and re-addition of CoQ to plasma membranes.
- Assays for NADH dehydrogenase and oxidoreductase activity.
- Inhibition studies using CoQ analogs.
- Measurement of ferricyanide reduction and proton release in HeLa cells.
- Cell growth assays for HeLa and BALB/3T3 cells.
Main Results:
- CoQ extraction decreased NADH dehydrogenase and oxidoreductase activity in rat hepatocytes and human erythrocytes.
- CoQ addition restored these activities, with partial restoration by alpha-tocopherylquinone but not vitamin K1.
- CoQ analogs inhibited ferricyanide reduction and proton release in HeLa cells, effects reversed by CoQ10.
- CoQ10 addition enhanced the growth of serum-deficient HeLa and BALB/3T3 cells.
Conclusions:
- Coenzyme Q is crucial for trans-plasma membrane electron transport.
- TPMET, influenced by CoQ, plays a role in stimulating cell growth.