Some properties of purified hepatoredoxin from bovine liver mitochondria

Some of the most important physicochemical properties of hepatoredoxin from bovine liver, purified to a homogeneous state, were determined for the first time. The protein contains a [2Fe-2S] cluster in its active site and in an oxidized state has absorption maxima at 280, 320, 415, and 455 nm. The spectrophotometric index of purity (A415/A280) of the homogeneous native preparation is 0.84; the extinction coefficient (epsilon415) is equal to 9800 M-1 cm-1. According to the data of gel electrophoresis in the presence of SDS, hepatoredoxin has an M/sub r/ of 12,500; its isoelectric point (pI) is equal to 4.2. Hepatoredoxin is necessary for the reconstitution of the C27-steroid hydroxylase activity and can be replaced by the related protein, adrenodoxin. All the parameters listed above, as well as the CD spectra, the immunochemical properties, and sequence of the first five N-terminal amino acids of hepatoredoxin and adrenodoxin are very similar of identical. At the same time, the amino acid composition of the two ferredoxins, along with common properties, has some differences