A novel fluorescent reagent for hydroperoxides, 4-(2-diphenylphosphinoethylamino)-7-nitro-2,1,3-benzoxadiazole (1), was developed on the basis of the method for designing photoinduced electron transfer (PET) reagents having a benzofurazan skeleton. Compound 1 was quantitatively reacted with hydroperoxides to give its fluorescent derivative, 2. In acetonitrile, the Phi value (0.44) of 2 was 31 times greater than that of 1. The long excitation (458 nm) and emission (520 nm) wavelengths of 2 are suitable for the determination of hydroperoxides, especially in biosamples. [structure: see text]

To develop new photoinduced electron-transfer (PET) reagents, we established a method for predicting the fluorescence quantum yields (phi) of the benzofurazan compounds bearing an aliphatic substituent group having an n-electron. The PET process occurred sufficiently to reduce the phi values in the benzofurazan compounds bearing an aliphatic moiety, which had a high quenching ability. The quenching ability was estimated by the molecular orbital calculation and Stern-Volmer plotting. The phi values of the benzofurazan compounds could be controlled by changing the quenching ability of a substituent group. We succeeded in designing a PET reagent for peroxyacetic acid (PAA), 4-ethylthioacetylamino-7-phenylsulfonyl-2,1,3-benzoxadiazole (EPB), using the established method for predicting the phi values. EPB and its oxidized derivative were separated by reversed-phase HPLC and fluorometrically detected at 479 nm with excitation at 362 nm. The attained detection limit for PAA was 105 fmol (S/N = 3) and the cross-reactivity toward hydrogen peroxide was very low, indicating EPB is a highly sensitive and selective reagent for PAA.

Urolithiasis is a common complication in patients with hypouricemia. Using a microarea x-ray diffractometer and nanoflow liquid chromatography-mass spectrometry (LC-MS) following SDS-polyacrylamide gel electrophoresis (PAGE), recurrent urinary calculi complicating a hypouricemic patient were analyzed. Analysis with the microarea x-ray diffractometer showed that one of the calculi was composed of calcium oxalate monohydrate and hydroxyapatite. The other was found to be formed from calcium oxalate dihydrate. After determination with LC-MS, both were found to contain uromodulin, albumin, osteopontin, protein Z, and defensins. Lysozyme and calgranulin A were also identified in these calculi. Defensins, which were antimicrobial peptides, and lysozyme, a mucopeptide glycohydrolase, were identified as new organic components of urinary stones. The role of these proteins in the process of urolithiasis is of particular interest.

No abstract

No abstract