The application of high-performance liquid chromatography (HPLC) using a C30 reverse-phase stationary matrix has enabled the simultaneous separation of carotenes, xanthophylls, ubiquinones, tocopherols and plastoquinones in a single chromatogram. Continuous photodiode array (PDA) detection ensured identification and quantification of compounds upon elution. Applications of the method to the characterization of transgenic and mutant tomato varieties with altered isoprenoid content, biochemical screening of Arabidopsis thaliana, and elucidation of the modes of action of bleaching herbicides are described to illustrate the versatility of the procedure.

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Summary The application of high‐performance liquid chromatography (HPLC) using a C30 reverse‐phase stationary matrix has enabled the simultaneous separation of carotenes, xanthophylls, ubiquinones, tocopherols and plastoquinones in a single chromatogram. Continuous photodiode array (PDA) detection ensured identification and quantification of compounds upon elution. Applications of the method to the characterization of transgenic and mutant tomato varieties with altered isoprenoid content, biochemical screening of Arabidopsis thaliana, and elucidation of the modes of action of bleaching herbicides are described to illustrate the versatility of the procedure.

The gene encoding component S, the small subunit1 of glutamate mutase, an adenosylcobalamin (coenzyme B12)‐dependent enzyme from Clostridium tetanomorphum has been cloned and its nucleotide sequence determined. The mutS gene encodes a protein of 137 amino acid residues, with M r, 14,748. The deduced amino acid sequence showed homology with the C‐terminal portion of adenosylcobalamin‐dependent methylmalonyl‐CoA mutase [1989, Biochem. J. 260, 343–352] and a region of cobalamin‐dependent methionine synthase which has been shown to bind cobalamin [1989, J. Biol. Chem 264, 13888–13895].

We have determined the structure of wild-type IP-10 from three crystal forms. The crystals provide eight separate models of the IP-10 chain, all differing substantially from a monomeric IP-10 variant examined previously by NMR spectroscopy. In each crystal form, IP-10 chains form conventional beta sheet dimers, which, in turn, form a distinct tetrameric assembly. The M form tetramer is reminiscent of platelet factor 4, whereas the T and H forms feature a novel twelve-stranded beta sheet. Analytical ultracentrifugation indicates that, in free solution, IP-10 exists in a monomer-dimer equilibrium with a dissociation constant of 9 microM. We propose that the tetrameric structures may represent species promoted by the binding of glycosaminoglycans. The binding sites for several IP-10-neutralizing mAbs have also been mapped.