Fat Metabolism in Higher Plants. VI. Incorporation of P32 into Peanut Mitochondrial Phospholipids.

Abstract

The incorporation of P32 into the phospholipid fraction of peanut cotyledon mitochondria has been described. The first step on the route of incorporation is the esterification of P32 into ATP32. This step requires an adenine nucleotide, Mg++ and a Krebs cycle intermediate. The nucleotide requirement can be satisfied by either AMP, ADP or ATP. The incorporation into ATP32 is oxygen dependent and is sensitive to dinitrophenol. Only freshly prepared mitochondria can perform this step. The maximum amount of incorporation was 0.35% of the added P. The steps from ATP32 to lipid phosphorus are unknown. Mg++ is required, and either fresh, frozen or lyophilized mitochondria can perform this sequence. Dinitrophenol has no effect on this portion of the route of P32. The phospholipid which becomes labeled is unknown. Chromatographic studies have shown it is not phosphatidyl choline, phosphatidyl serine, phosphatidyl ethanolamine, or a phosphatidic acid.