4 FERREDOXINS FROM JAPANESE RADISH LEAVES

We detected three ferredoxin components, a, b, and c, in green shoots of Japanese radish seedlings by hydrophobic HPLC analysis using a phen yl-5PW column. All components were also present in mature leaves. Comp onent a was further separated into two components, a(1) and a(2), by r eversed-phase HPLC after carboxymethylation. The existence of four fer redoxins in the photosynthetic tissue of a single plant species is rep orted here for the first time. Each individual ferredoxin component wa s isolated, and its primary structure was analyzed for comparison with the two leaf ferredoxins, L-Fds A and B, isolated by Wada et al. (J. Biochem. 105, 619-625 (1989)). The primary structures of components a( 1), a(2), and b were all found in 12 possible structures of L-Fd A ded ucible from its microheterogeneities. This led us to conclude that L-F d A is a mixture of three ferredoxins corresponding to components a(1) , a(2), and b. The complete primary structure of component c was estab lished by sequencing of the whole protein and of peptides generated by protease digestion. The N-terminal structure of component c was ident ical with L-Fd B up to the 11th amino acid residue, suggesting that th is component is the same ferredoxin as L-Fd B. (C) 1995 Academic Press , Inc.