scholarly journals The significance of cytochrome c redistribution during the subcellular fractionation of rat liver

1968 ◽  
Vol 107 (4) ◽  
pp. 523-529 ◽  
Author(s):  
N. F. González-Cadavid ◽  
María Bravo ◽  
P. N. Campbell
Keyword(s):  
Sodium Chloride ◽  
Cytochrome C ◽  
Subcellular Fractionation ◽  
Mitochondrial Fraction ◽  
Soluble Form ◽  
Mitochondrial Cytochrome ◽  
Whole Process ◽  
Soluble Cell ◽  
Mitochondrial Cytochrome C

1. The redistribution of mitochondrial cytochrome c during homogenization and subcellular fractionation of the liver was studied. Chromatographically homogeneous 14C-labelled cytochrome c was added in different amounts to liver suspensions immediately before homogenization and the adsorption of radioactivity was determined in cytochrome c fractions extracted at pH4·0, first with water and then with 0·15m-sodium chloride. 2. The soluble cytochrome c remaining in the cell sap after subcellular fractionation was 7% of the calculated amount of cytochrome c passing through a soluble form during the whole process. The total amount of cytochrome c released in a soluble form and subsequently redistributed was 25–30% of the total liver cytochrome c. 3. In the standard microsomal fraction the cytochrome c extracted with water originated entirely from redistribution whereas that extracted with 0·15m-sodium chloride was 80% endogenous. In the mitochondrial fraction both cytochrome c pools were truly endogenous, so that practically none of the mitochondrial cytochrome c released to the soluble cell sap was readsorbed by the mitochondria. 4. These results support our former hypothesis that the cytochrome c extracted with 0·15m-sodium chloride at pH4·0 from the standard microsomes represents the cytochrome c newly synthesized in situ, since it does not originate from redistribution. However, the microsomal pool extracted with water cannot be an intermediate in the postulated transfer of cytochrome c from the microsomal particles to the mitochondria, since this pool arises from redistribution of mitochondrial cytochrome c.

scholarly journals The biosynthesis of cytochrome c. Sequence of incorporation in vivo of [14C]lysine into cytochrome c and total proteins of rat-liver subcellular fractions

1967 ◽  
Vol 105 (2) ◽  
pp. 443-450 ◽  
Author(s):  
N. F. González-Cadavid ◽  
P. N. Campbell
Keyword(s):  
Sodium Chloride ◽  
Cytochrome C ◽  
Total Protein ◽  
Microsomal Fraction ◽  
Specific Radioactivity ◽  
Subcellular Fractions ◽  
Nuclear Fraction ◽  
Mitochondrial Cytochrome ◽  
Peak Value ◽  
Mitochondrial Cytochrome C

1. In order to determine the initial intracellular site of synthesis of cytochrome c in the liver cell, groups of rats were injected with [14C]lysine and killed 7·5, 15, 30 and 60min. later. The livers were homogenized in 0·3m-sucrose and subcellular fractions obtained. The mitochondrial fraction was further subfractionated. Pure cytochrome c was isolated from extracts of each fraction, obtained first with water at pH4·0 and then with 0·15m-sodium chloride. 2. A comparison of the kinetics of incorporation of [14C]lysine into total protein for each particulate fraction showed the usual two different kinds of kinetics. Incorporation into all the mitochondrial subfractions and the nuclear fraction rose gradually to a plateau value at about 20min., in contrast with that into the two microsomal fractions which rose rapidly to a peak value about seven times that for the mitochondrial fractions. The kinetics for the incorporation into mitochondrial cytochrome c showed a plateau value at 30min. about three times that for the total mitochondrial protein. There was no difference in the specific radioactivity of the mitochondrial cytochrome c extracted with water or 0·15m-sodium chloride or between the different mitochondrial subfractions. In contrast, the cytochrome c isolated from water extracts of the microsomal fractions had a lower specific radioactivity than that obtained from the 0·15m-sodium chloride extract. The specific radioactivity of the latter showed a rapid rise to a peak value about four times that for the mitochondrial cytochrome c, and the shape of the curve was similar to that for the total protein of the microsomal fraction. The results suggest that cytochrome c is synthesized in toto by the morphological components of the microsomal fraction. It seems first to be bound tightly to a microsomal particle, passing then to a looser microsomal binding and being finally transferred to the mitochondria. The newly synthesized cytochrome c in the mitochondrion could not be differentiated from the old by its degree of extractability at pH 4·0.

scholarly journals A genome-wide copper-sensitized screen identifies novel regulators of mitochondrial cytochrome c oxidase activity

2021 ◽  
Vol 296 ◽  
pp. 100485
Author(s):  
Natalie M. Garza ◽  
Aaron T. Griffin ◽  
Mohammad Zulkifli ◽  
Chenxi Qiu ◽  
Craig D. Kaplan ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Oxidase Activity ◽  
Mitochondrial Cytochrome ◽  
Genome Wide ◽  
A Genome ◽  
Mitochondrial Cytochrome C

Uranium inhibits mammalian mitochondrial cytochrome c oxidase and ATP synthase

2021 ◽  
Vol 271 ◽  
pp. 116377
Author(s):  
Libing Yu ◽  
Wenjing Li ◽  
Jian Chu ◽  
Chun Chen ◽  
Xijian Li ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Atp Synthase ◽  
Mitochondrial Cytochrome ◽  
Mitochondrial Cytochrome C
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