We examined the contents of different vegetables using X-ray fluorescence spectrometry and found extremely high levels of bromine (Br) [1000-16200 ppm (dry weight)] in some vegetables from an Osaka market. Examination using a bromide ion-selective electrode suggested that the bromine existed mainly as bromide ion. Since this bromine probably originated from fumigation with methyl bromide, this result suggests that fumigation methods may need to be regulated. Fifty milligrams of bromine [aceptable daily intake (ADI)/50 kg] was found in only 3.1 g (dry weight) of komatsuna (Br: 16200 ppm). These results suggest that vegetables that contain potentially harmful levels of bromide may be found in Japanese markets.
We have proposed the term 'protein chemotaxonomy' for molecular taxonomy based on the primary structures of common plant proteins, instead the of so-called secondary metabolites. To evaluate the effectiveness of this concept, we have carried out a series of studies on the family Solanaceae, using ferredoxin (Fd), an iron-sulfur electron-transfer protein.2) This protein was chosen for this study because it is easy to isolate and has an appropriate molecular weight for determining the primary structure. Previously, we have reported the primary structures of Fds from seven Datura plants [3][4][5][6] and other solanaceous plants 7-11) Our recent results have suggests that S. japonica is closely related taxonomically to Datura plants, and especially to D. arborea. Interestingly, both S. japonica and Datura plants contain tropane-alkaloids such as hyoscyamine, atropine, and scopolamine. It may be worthwhile to determine the relationship between pharmacologically important constituents and the amino acid sequences of Fds from these plants. These considerations led us to elucidate the amino acid sequences of Fds from Atropa belladonna and Hyoscyamus niger, which are important medicinal plants that contain tropane-alkaloids.In this report, we determined the primary structures of Fds from A. belladonna and H. niger (Solanaceae), and compared them with those of Fds from other higher plants as well as those from Datura plants and other solanaceous plants. MATERIALS AND METHODS Materials Atropa belladonna and Hyoscyamus nigerwere cultivated in the herb garden at Osaka University of Pharmaceutical Sciences.Isolation of Ferredoxin Each protein (15.4 or 3.0 mg) was purified from the fresh leaves (0.6 or 0.5 kg) of A. belladonna or H. niger as described previously. 3,7)Sequence Determination The amino acid sequences of the Fds were determined using a gas-phase protein sequencer with automated Edman degradation of S-carboxymethylcysteinyl (Cm) Fd and the peptides obtained by lysyl endopeptidase, trypsin, or endoproteinase Asp-N digestion. C-terminal analysis was carried out with carboxypeptidase Y.The detailed procedure and the other methods have been described previously. 3,7)Construction of a Phylogentic Tree A phylogenetic tree was constructed from the amino acid sequences (97 residues) of higher-plant Fds (30 species) using the unweighed pairgroup method with the arithmetical averages (UPGMA) method of Nei (GENETYX software, Software Development, Japan). 13) The molar absorption coefficient at 420 nm, based on the spectrum and protein determination, was 11000 M Ϫ1 cm Ϫ1 , which was similar to those of other higher-plant Fds.2,13) The biological activities and other physico-chemical properties of Ab-and HnFds will be published elsewhere, together with those of other solanaceous Fds.Sequence Determination The sequencing strategy is summarized in Fig. 1. The analytical results regarding the amino acid compositions of both Cm-Fds and the peptides obtained by enzymatic digestion, were consistent with the derived sequences. Automat...
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