Cell-free synthesis and characterization of human adrenocortical pro-adrenodoxin

Poly(A+)-RNAs were extracted from human hyperplasic adrenocortical tissue and translated in a wheat germ cell-free system in the presence of [35S]-methionine. Labeled immuno-reactive adrenodoxin (ADX)-like material was immunoisolated and examined following mono and bi-dimensional electrophoretic analysis. Bovine mRNA translation products were analysed under similar conditions. While it was confirmed that bovine ADX was synthesized as a precursor of Mr 21 kDa, human pro-ADX was characterized for the first time as a somewhat larger moiety (24 kDa). On the other hand, both human and bovine mature mitochondrial ADX showed a Mr of 12 kDa. Electrophoretic study disclosed that the human, as well as the bovine pro-ADX could be resolved into several components differing by their pHi (6.5 and 6.9 for h-proADX and 5.9, 6.1 and 6.2 for b-proADX, respectively). This molecular heterogeneity might be explained by discrete disparity in the pro-adrenodoxin amino acid contents.