Phosphatidylserine was labeled by incubating rat brain homogenates with [3-I4C]serine in the presence of Ca2+ (base-exchange conditions). Some labeled phosphatidylethanolamine also forms, in spite of the inhibition of Ca" on phosphatidylserine decarboxylase. Phosphatidylserine labeling and decarboxylation also occur on incubating a mixture of purified mitochondria and microsomes, suggesting that no soluble factors are necessary for the synthesis and the decarboxylation of phosphatidylserine. Ca2+ favors the transfer of phosphatidylserine from microsomes (where it forms) to mitochondria (where it is decarboxylated). The specific radioactivity of the phosphatidylserine transferred to mitochondria is higher than that of microsoma1 phosphatidylserine. This finding supports the hypothesis that the lipid is compartmentalized in microsomes and that radioactive, newly synthesized phosphatidylserine is much better exported than the bulk of microsomal phospholipid. Key Words: Phosphatidylserine-Base-exchange reactions-Phosphatidylserine decarboxylase-Mitochondria- Microsomes-Brain. Corazzi L. et al. Transport of phosphatidylserine from microsomes to the inner mitochondrial membrane in brain tissue. J. Neurochem. 60,50- 56 (1 993).
Transport of phosphatidylserine from microsmes to the inner mitochondrial membrane in brain tissue
CORAZZI, Lanfranco;
1993
Abstract
Phosphatidylserine was labeled by incubating rat brain homogenates with [3-I4C]serine in the presence of Ca2+ (base-exchange conditions). Some labeled phosphatidylethanolamine also forms, in spite of the inhibition of Ca" on phosphatidylserine decarboxylase. Phosphatidylserine labeling and decarboxylation also occur on incubating a mixture of purified mitochondria and microsomes, suggesting that no soluble factors are necessary for the synthesis and the decarboxylation of phosphatidylserine. Ca2+ favors the transfer of phosphatidylserine from microsomes (where it forms) to mitochondria (where it is decarboxylated). The specific radioactivity of the phosphatidylserine transferred to mitochondria is higher than that of microsoma1 phosphatidylserine. This finding supports the hypothesis that the lipid is compartmentalized in microsomes and that radioactive, newly synthesized phosphatidylserine is much better exported than the bulk of microsomal phospholipid. Key Words: Phosphatidylserine-Base-exchange reactions-Phosphatidylserine decarboxylase-Mitochondria- Microsomes-Brain. Corazzi L. et al. Transport of phosphatidylserine from microsomes to the inner mitochondrial membrane in brain tissue. J. Neurochem. 60,50- 56 (1 993).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
