The spectral properties of several azulene-oxazolone derivatives containing a phenyloxazolone moiety linked to substituted azulene ring via C=C double bond were studied in different solvents varying polarity. solvatochromism and the ability recognize heavy metal ions investigated. In order estimate contribution non-specific specific solute–solvent interactions, multiple linear regression analys...

A metagenomic library of surface-water microbes from the Yangtze River in China was constructed, and a novel esterase, designated as EstY, was isolated and characterized. EstY had 423 amino acids with an estimated molecular mass of 44 kDa and pI of 7.28. It hydrolyzed various pnitrophenyl esters (acetate, butyrate, caprate, caprylate, laurate, myristate, and palmitate) and its best substrate wa...

A facile supported liquid membrane (SLM) system for the selective and efficient transport of silver ion is introduced. The SLM used is a thin porous polyvinyldifluoride membrane impregnated with hexathia-18-crown-6 (HT18C6) dissolved in nitrophenyloctyl ether. HT18C6 acts as a specific carrier for the uphill transport of Ag+ ion as its picrate ion paired complex through the SLM. In the presence...

Fructan-hydrolyzing enzyme from Streptococcus salivarius KTA-19 isolated from human dental plaque was investigated. The enzyme was purified by ammonium sulfate precipitation, acetone fractionation, and column chromatography on Bio-Gel and DEAE-cellulose. The purified enzyme showed a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric focusing. Its molecular ...

Enzymatic browning reactions by polyphenol oxidases cause alteration of appearance, flavor and nutritive value vegetables fruits. It is one the important problems for used as salads causes lots economic losses. In this study, oxidase (PPO) from Eruca sativa was extracted characterization studies were carried out. Substrate specificity variable substrates, optimum pH, temperature, effect differe...

An investigation of the Hg2+ resistance mechanism of four freshwater and four coastal marine bacteria that did not hybridize with a mer operonic probe was conducted (T. Barkay, C. Liebert, and M. Gillman, Appl. Environ. Microbiol. 55:1196-1202, 1989). Hybridization with a merA probe, the gene encoding the mercuric reductase polypeptide, at a stringency of hybridization permitting hybrid formati...

A time-dependent inhibition of the thyrotropin-releasing-hormone (TRH)-degrading ectoenzyme (EC 3.4.19.-) from rat brain by the metal-complexing agents imidazole, NaCN, EDTA and 1,10-phenanthroline could be demonstrated. In contrast, the inhibition by the non-chelating analogues 4,7and 1,7-phenanthroline was not time-dependent. At a concentration of 100 ,M EDTA the enzymic activity decreased by...

The activity of UDP-glucuronosyltransferase (UDPGT, EC 2.4.1.17) in human foetal liver cells in culture was measured with two acceptor substrates, namely harmol and 1-naphthol. There was a dose-dependent increase of about 10-400% in UDPGT activity when the cells were exposed to 1-30 microM-HgCl2. Above a critical concentration of 30 microM-HgCl2, the heavy metal ion was toxic to the cells. Kine...