Biochemistry of Polyglycerophosphatides. The Mechanism of Cardiolipin Biosynthesis in Isolated Mitochondria

1973 ◽  
Vol 51 (3) ◽  
pp. 286-304 ◽  
Author(s):  
N. Z. Stanacev ◽  
J. B. Davidson ◽  
L. Stuhne-Sekalec ◽  
Z. Domazet
Keyword(s):  
Reaction Mechanism ◽  
Liver Mitochondria ◽  
Water Soluble ◽  
Rat Liver Mitochondria ◽  
Labeled Compounds ◽  
Experimental Conditions ◽  
Isolated Rat Liver ◽  
Isolated Mitochondria ◽  
Membrane Bound ◽  
Isolated Rat

The mechanism of cardiolipin biosynthesis in isolated rat liver mitochondria was studied using endogenously formed and exogenously supplied phosphatidylglycerol-2′-3H in the presence and absence of added Mg2+, Mn2+, CDP-DL-dioleate, and CDP-D-diglyceride-2-14C. With endogenously formed and membrane-bound phosphatidylglycerol-2′-3H and in the presence of Mn2+, the incorporation of CDP-D-diglyceride-2-14C into cardiolipin-3H,14C was demonstrated, establishing the participation of both phosphatidylglycerol-2′-3H and CDP-D-diglyceride-2-14C in the formation of cardiolipin-3H,14C. In addition, the release of water-soluble labeled compounds was measured and the efficiency of glycerol-2-3H recovery after the incubation with mitochondria was determined. It was concluded that under the described experimental conditions the formation of cardiolipin in isolated mitochondria takes place according to the reaction mechanism: phosphatidylglycerol + CDP-diglyceride → cardiolipin. Some aspects of these findings are discussed in detail

scholarly journals Protein-mediated uptake of vitamin B12 by isolated mitochondria

Blood ◽  
1976 ◽  
Vol 47 (6) ◽  
pp. 923-930 ◽  
Author(s):  
RA Gams ◽  
EM Ryel ◽  
F Ostroy
Keyword(s):  
Vitamin B12 ◽  
Rat Liver ◽  
Mitochondrial Respiration ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Isolated Rat Liver ◽  
Isolated Mitochondria ◽  
Isolated Rat

Abstract Protein-mediated B12 uptake by isolated rat liver mitochondria has been shown to be enhanced by plasma transcobalamin (TC-II) but not by salivary R binder in vitro. The process is enhanced by calcium and depends on active mitochondrial respiration. Following uptake, cyanocobalamin is converted to adenosyl and methylcobalamins and released from the mitochondria. TC-II appears to be required for both cellular and mitochondrial uptake of vitamin B12.

scholarly journals Protein-mediated uptake of vitamin B12 by isolated mitochondria

Blood ◽  
1976 ◽  
Vol 47 (6) ◽  
pp. 923-930
Author(s):  
RA Gams ◽  
EM Ryel ◽  
F Ostroy
Keyword(s):  
Vitamin B12 ◽  
Rat Liver ◽  
Mitochondrial Respiration ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Isolated Rat Liver ◽  
Isolated Mitochondria ◽  
Isolated Rat

Protein-mediated B12 uptake by isolated rat liver mitochondria has been shown to be enhanced by plasma transcobalamin (TC-II) but not by salivary R binder in vitro. The process is enhanced by calcium and depends on active mitochondrial respiration. Following uptake, cyanocobalamin is converted to adenosyl and methylcobalamins and released from the mitochondria. TC-II appears to be required for both cellular and mitochondrial uptake of vitamin B12.

scholarly journals Importance of the osmolarity of the incubation medium on amino acid incorporation into protein by isolated rat liver mitochondria

1969 ◽  
Vol 111 (5) ◽  
pp. 653-663 ◽  
Author(s):  
D. Haldar ◽  
K. B. Freeman
Keyword(s):  
Protein Synthesis ◽  
Rat Liver ◽  
Inhibitory Action ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Isolated Rat Liver ◽  
Mitochondrial Ribosomes ◽  
Isolated Mitochondria ◽  
Escherichia Coli B ◽  
Isolated Rat

1. Incorporation of [14C]leucine into protein by isolated rat liver mitochondria was examined by using incubation media similar to those used by Sandell, Löw & Decken (1967) (medium A) and Roodyn, Reis & Work (1961) (medium B). The incorporation process was found to be almost completely inhibited in medium A. 2. By decreasing the amount of sucrose and omitting tris–hydrochloric acid from medium A, incorporation proceeded at a rate higher than that found in medium B. It was found that the inhibitory action of medium A was due to its high osmolarity. 3. Oxidative phosphorylation and RNA synthesis by the isolated mitochondria proceeded at the same rate in media essentially the same as media A and B. 4. There was a partial inhibitory action of medium A on leucine uptake by the mitochondria and also on the formation of leucyl-transfer-RNA. The major block of inhibition by the hyperosmolarity of medium A seemed to be located at a later step of protein synthesis involving mitochondrial ribosomes. 5. Protein synthesis by Escherichia coli B was only slightly inhibited, if at all, in hyperosmotic media in which protein synthesis by isolated mitochondria was completely stopped.

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