scholarly journals Androgens regulate mitochondrial cytochrome c oxidase and lysosomal hydrolases in mouse skeletal muscle

1980 ◽  
Vol 192 (1) ◽  
pp. 349-353 ◽  
Author(s):  
H Koenig ◽  
A Goldstone ◽  
C Y Lu
Keyword(s):  
Skeletal Muscle ◽  
Cytochrome C ◽  
Monoamine Oxidase ◽  
Cytochrome C Oxidase ◽  
Mitochondrial Membrane ◽  
Inner Mitochondrial Membrane ◽  
Lysosomal Hydrolases ◽  
Mouse Skeletal Muscle ◽  
Membrane Enzyme ◽  
Specific Activities

The gastrocnemius, a fast-twitch white muscle, and the soleus, a slow-twitch red muscle, were studied in A/J mice. The specific activities of the lysosomal hydrolases, beta-D-glucuronidase, hexosaminidase, beta-D-galactosidase and arylsulphatase, the inner-mitochondrial-membrane enzyme cytochrome c oxidase, and the outer-mitochondrial-membrane enzyme monoamine oxidase, were greater in the soleus than in the gastrocnemius. The specific activities of the lysosomal hydrolases and cytochrome c oxidase in the gastrocnemius and soleus were substantially higher in male mice than in female mice. Orchiectomy abolished this sex difference. Testosterone increased the activities of the lysosomal hydrolases and cytochrome c oxidase and coincidentally induced muscle hypertrophy and an accretion of protein and RNA, but total DNA remained constant. Monoamine oxidase was unaffected by sex, orchiectomy and testosterone. These findings indicate that endogenous androgens regulate the activity of enzymes associated with lysosomes and the inner mitochondrial membrane, as well as muscle fibre growth in mouse skeletal muscle.

scholarly journals Mitochondrial cytochrome c oxidase: catalysis, coupling and controversies

2017 ◽  
Vol 45 (3) ◽  
pp. 813-829 ◽  
Author(s):  
Peter R. Rich
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Mitochondrial Membrane ◽  
Mitochondrial Cytochrome ◽  
Inner Mitochondrial Membrane ◽  
Reaction Cycle ◽  
Chemical Structures ◽  
Catalytic Intermediates ◽  
Underlying Mechanisms ◽  
Mitochondrial Cytochrome C

Mitochondrial cytochrome c oxidase is a member of a diverse superfamily of haem–copper oxidases. Its mechanism of oxygen reduction is reviewed in terms of the cycle of catalytic intermediates and their likely chemical structures. This reaction cycle is coupled to the translocation of protons across the inner mitochondrial membrane in which it is located. The likely mechanism by which this occurs, derived in significant part from studies of bacterial homologues, is presented. These mechanisms of catalysis and coupling, together with current alternative proposals of underlying mechanisms, are critically reviewed.

Structure and function of Pet100p, a molecular chaperone required for the assembly of cytochrome c oxidase in Saccharomyces cerevisiae

2001 ◽  
Vol 29 (4) ◽  
pp. 436-441 ◽  
Author(s):  
D. Forsha ◽  
C. Church ◽  
P. Wazny ◽  
R. O. Poyton
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Molecular Chaperone ◽  
Mitochondrial Membrane ◽  
Protein Complexes ◽  
Structure And Function ◽  
Eukaryotic Cells ◽  
Mitochondrial Membranes ◽  
Inner Mitochondrial Membrane ◽  
And Function

The assembly of cytochrome c oxidase in the inner mitochondrial membranes of eukaryotic cells requires the protein products of a large number of nuclear genes. In yeast, some of these act globally and affect the assembly of several respiratory-chain protein complexes, whereas others act in a cytochrome c oxidase-specific fashion. Many of these yeast proteins have human counterparts, which when mutated lead to energy-related diseases. One of these proteins, Pet100p, is a novel molecular chaperone that functions to incorporate a subcomplex containing cytochrome c oxidase subunits VII, VIIa and VIII into holo-(cytochrome c oxidase). Here we report the topological disposition of Pet100p in the inner mitochondrial membrane and show that its C-terminal domain is essential for its function as a cytochrome c oxidase-specific ‘assembly facilitator’.

Role of phospholipid fatty acids on the kinetics of high and low affinity sites of cytochrome c oxidase

1986 ◽  
Vol 64 (11) ◽  
pp. 1195-1210 ◽  
Author(s):  
A. Trivedi ◽  
D. J. Fantin ◽  
E. Reno Tustanoff
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Membrane Fluidity ◽  
Mitochondrial Membrane ◽  
Polar Head Group ◽  
Mitochondrial Membranes ◽  
Inner Mitochondrial Membrane ◽  
High Affinity

The nature of the interactions between cytochrome c oxidase and the phospholipids in mitochondrial membranes has been investigated by varying the nature of the fatty acyl components of Saccharomyces cerevisiae. A double fatty acid yeast mutant, FAI-4C, grown in combinations of unsaturated (oleic, linoleic, linolenic, and eicosenoic) and saturated (lauric and palmitic) fatty acids, was employed to modify mitochondrial membranes. The supplemented fatty acids constituted a unique combination of different acyl chain lengths with varying degrees of unsaturation which were subsequently incorporated into mitochondrial phospholipids. Phosphatidylethanolamine and cardiolipin, the predominant phospholipids of the inner mitochondrial membrane, were characterized by their high levels of supplemented unsaturated fatty acids. Increasing the chain length or the degree of unsaturation of mitochondrial membrane phospholipids had no effect on altering the nature of the phospholipid polar head group but did result in a profound change on the specific activity of cytochrome c oxidase. When studied under conditions of different ionic strengths and pHs the enzyme's activity, as documented by Eadie–Hofstee plots, showed biphasic kinetics. The kinetic parameters for the low affinity reaction were greatly influenced by the changes in the membrane fatty acids and only marginal effects were noted at the high affinity reaction site. The discontinuities in the steady-state fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene, monitored at increasing temperatures, suggested that changes in membrane fluidity were conditioned by alterations in mitochondrial membrane fatty acid constituents. These results indicate that the lipid changes affecting the low affinity binding site of cytochrome c oxidase may be the result of lipid–protein interactions which lead to enzyme conformational changes or may be due to gross changes in membrane fluidity. It may, therefore, follow that this enzyme site may be embedded in or be juxtaposed to the outer surface of the inner mitochondrial membrane bilayer in contrast to the high affinity site which has been shown to be significantly above the membrane plane.

scholarly journals Flux Control of Cytochrome c Oxidase in Human Skeletal Muscle

2000 ◽  
Vol 275 (36) ◽  
pp. 27741-27745 ◽  
Author(s):  
Wolfram S. Kunz ◽  
Alexei Kudin ◽  
Stefan Vielhaber ◽  
Christian E. Elger ◽  
Giuseppe Attardi ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Human Skeletal Muscle ◽  
Flux Control
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