Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.9.3.1 (cytochrome oxidase)
 8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cells from a rapidly growing rat Zajdela hepatoma were shown to contain (on a protein basis) five-times less mitochondria than hepatocytes from resting or regenerating rat liver. Transcripts of four nuclear genes for representative mitochondrial membrane proteins (beta-F1 subunit and N,N'-dicyclohexyl-carbodiimide-binding protein of ATP synthase, subunit IV of cytochrome oxidase and ADP/ATP translocase) were present in 2-4 times higher amounts in the poly(A)-rich RNA of the hepatoma than in the corresponding RNA fraction from resting or regenerating rat liver. The liver and hepatoma transcripts for the beta-F1 subunit were translated in an in-vitro system with equal efficiency. Pulse-chase labeling of isolated Zajdela hepatoma cells and hepatocytes from resting and regenerating liver revealed a relative excess of the newly synthesized beta-F1 subunit in the tumor cells. The half-life of the beta-F1 subunit was significantly shorter in the hepatoma cells than in hepatocytes from resting and regenerating liver. The contents of transcripts of three mitochondrial genes examined (cytochrome oxidase subunits I and II and NADH-ubiquinone reductase subunit 2) in Zajdela hepatoma mitochondria were about five-times higher than in the mitochondria of the resting cells and 3-4 times higher than in the organelles of the regenerating organ. The results indicate that events other than transcription (most likely post-translational) may be responsible for the reduced content of mitochondria in tumor cells.
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PMID:Increased steady-state levels of several mitochondrial and nuclear gene transcripts in rat hepatoma with a low content of mitochondria. 137 34

The stoichiometry and dissociation constant for the binding of homogeneous chicken heart mitochondrial creatine kinase (MiMi-CK) to mitoplasts was examined under a variety of conditions. Salts and substrates release MiMi-CK from mitoplasts in a manner that suggests an ionic interaction. The binding of MiMi-CK to mitoplasts is competitively inhibited by Adriamycin, suggesting that they compete for the same binding site. Fluorescence measurements also show that Adriamycin binds to MiMi-CK so that the effect of Adriamycin on the binding of MiMi-CK to mitoplasts is not simple. Titrating mitoplasts with homogeneous MiMi-CK at different pH values shows a pH-dependent equilibrium involving a group(s) on either the membrane or the enzyme with a pKa = 6. Extrapolating these titrations to infinite MiMi-CK concentration gives 14.6 IU bound/nmol cytochrome aa3 corresponding to 1.12 mol MiMi-CK/mol cytochrome aa3. Chicken heart mitochondria contain, after isolation, 2.86 +/- 0.42 IU/nmol cytochrome aa3. Titrating respiring mitoplasts with carboxyatractyloside gives at saturation 3.3 mol ADP/ATP translocase/mol cytochrome aa3. Therefore, chicken heart mitoplasts can maximally bind about 1 mol of MiMi-CK per 3 mol translocase; in normal chicken heart mitochondria about 1 mol of MiMi-CK is present per 13 mol translocase.
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PMID:Association of chicken mitochondrial creatine kinase with the inner mitochondrial membrane. 381 58