A series of N-acetyl-O-(ω-alkenyl)-L-tyrosine ethyl esters were synthesized by the reaction of vinyl bromides (4-bromo-1-butene, 6-bromo-1-hexene, 8-bromo-1-octene and 10-bromo-1-decene) with N-acetyl-L-tyrosine ethyl ester. 1H NMR, elemental analysis, FT-IR, and mass spectra were performed for these N-acetyl-O-(ω-alkenyl)-L-tyrosine ethyl esters. The novel titanium complex can catalyze the cop...

Multi-competitive enzymatic reactions were performed to determine the selectivity properties of enzymes immobilised in polyacrylamide-alginate (pAAm-Alg) microcapsules. The transesterification of fatty acid ethyl esters of different chain lengths (C2–C14) with various alcohols catalysed by the enzyme lipase Mucor Miehei was chosen as a test system. While the free enzyme exhibited higher selecti...

In a separate study on the orally active acyloxymethyl esters(1)of 7{2一(2-aminothiazol4-yl)acetamido}3一[[[1一(2-dimethylaminoethy1)一1H-tetrazol-5-y1】thio]methyl]ceph-3-em-4-carboxylic acid(cefotiam, CTM), we have shown, by quantitative structure-oral bioavailability (BA)relation analysis, that the R2 group in the acyl group R2CO must have both an adequate lipophilicity(HANscH's lipophilic parame...

Since the isolation and identification of the sesquiterpene antibiotic pentalenolactone (1),1-7) several other related metabolites have been recognized in strains of Streptomyces, notably pentalenolactones E (2),8,9) G (3),10) and H (4),11) pentalenic acid (5),11,12) and the parent hydrocarbon, pentalenene (6).11-15)* Besides their novel structural features, these compounds are all potential in...

Ethanolic leaf extract of Hyptis capitata Jacq. showed a toxic effect on Artemia salina larvae1. The was simplified through fractionation using vacuum liquid chromatography to trace compounds with biological activity. F1, F2, F3 and F4 fractions were used in the acute toxicity test A. larvae. F1 highest value 196.77±2.7 µg/ml. As an initial screening for its anticancer potential, ethanolic frac...

The ability of all-trans-retinoic acid (RA) and other retinoid derivatives to enhance DNA synthesis and to induce ornithine decarboxylase [L-ornithine carboxylyase; EC 4.1.1.17 (ODC)] activity has been investigated in normal and tape-stripped hairless mouse epidermis. Initial studies showed that the retinoids could inhibit the induction of epidermal ODC activity found 4.5 hr after tape strippin...

Acetate ester, which are produced by fermenting yeast cells in an enzyme-catalyzed intracellular reaction, are responsible for the fruity character of fermented alcoholic beverages such as Chinese yellow rice wine. Alcohol acetyltransferase (AATase) is currently believed to be the key enzyme responsible for the production of acetate ester. In order to determine the precise role of the ATF2 gene...