HeLa nuclear, mitochondrial and microsomal binding proteins for vitamin A compounds.

HeLa cells cultured in Eagle's medium incorporate and metabolize (3H) 11,12-retinyl acetate: TLC analysis of vitamin A extracts shows that no more than 7% of retinyl acetate is recovered from the cell sap, whole homogenate, nuclei, mitochondria and microsomes. Physiological active vitamin A compounds (retinol, retinal and retinoic acid) represent about 65% of the vitamin A extracted from homogenate, nuclei, mitochondria and microsomes. 1% SDS extracts of nuclei and mitochondria were analyzed by PAG electrophoresis. Nuclear electrophoregrams show vitamin A radioactivity in three zones of the gel corresponding to proteins with molecular weights of 15,000; 19,000 and 23,000 respectively. In mitochondrial electrophoregrams vitamin A radioactivity is located in three zones of the gel, corresponding to proteins with molecular weights of 16,500, 24,000 and 85,000 respectively.