Respiratory control and ADP:O coupling ratios of isolated chick heart mitochondria
| Autor: | Kendall J. Sumerix, Shelagh Ferguson-Miller, Clarence H. Suelter, Peter P. Toth |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Carbonyl Cyanide m-Chlorophenyl Hydrazone
Cellular respiration ATPase Biophysics chemistry.chemical_element Hydroxybutyrates Mitochondrion Biochemistry Oxygen Mitochondria Heart Oxidative Phosphorylation Divalent Electron Transport Complex IV chemistry.chemical_compound Oxygen Consumption Glutamates Respiration Animals Magnesium Pyruvates Molecular Biology Egtazic Acid Heart metabolism chemistry.chemical_classification Adenosine Triphosphatases biology 3-Hydroxybutyric Acid Succinates Adenosine Diphosphate EGTA Kinetics Microbial Collagenase chemistry Oxidative Phosphorylation Coupling Factors Ethylmaleimide biology.protein Ketoglutaric Acids Chickens |
| Zdroj: | Archives of biochemistry and biophysics. 276(1) |
| ISSN: | 0003-9861 |
| Popis: | Heart mitochondria isolated from 14- to 21-day-old chicks are highly coupled and often have respiratory control ratio (RCR) values exceeding 100. This paper presents data from a study of some of the properties of these mitochondria. The studies show that: (a) The ADP:O ratios and the state 4 rates of respiration are highly dependent upon the concentration of mitochondria at which these parameters are measured. (b) The mitochondrial isolate is contaminated with at least two divalent cation-stimulated ATPase, of which one is the F1F0-ATPase of broken mitochondria. (c) The oligomycin-sensitive component of state 4 respiration is completely inhibited by ethylene glycol bis(beta-amino-ethylether) N,N'-tetraacetic acid (EGTA). This inhibition is biphasic and attributable to the differential affinity of EGTA for Ca(II) and Mg(II). (d) Ca(II) and Mg(II) stimulate state 4 respiration, thereby depressing RCR values. These cations also decrease ADP:O ratios from greater than or equal to 3.25 to 3.0 for some NAD-linked substrates. (e) Uncoupled (i.e., oligomycin-insensitive) state 4 respiration can be abolished by treating the mitochondria with Nagarse and by preincubating mitochondria with exogenous substrate. (f) The ADP:O ratios obtained when these heart mitochondria oxidize pyruvate/malate, alpha-ketoglutarate, and beta-hydroxybutyrate are fractional and significantly greater than 3.0. |
| Databáze: | OpenAIRE |
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