The aminolysis of a mildly activated aminoacid ester, benzyloxycarbonyl-L-phenylalanine cyanomethyl ester, by glycine esters in the presence of catechol has been studied as a model of catalysis by RNA cis-vicinal-diol systems in protein biosynthesis. Catechol accelerated the aminolysis, especially in the presence of bases, probably by nucleophilic catalysis.

background: lipase is an enzyme with immense application potential. ester synthesis by lipase catalysis in organic media is an area of key industrial relevance. enzymatic preparations with traits that cater to the needs of this function are hence being intensely researched. objective: the objectives of the study were to immobilize the lipase from bacillus sp. ps35 by cross-linking and adsorptio...

Phenylalanine ammonia-lyase (RgPAL) from Rhodotorula glutinis JN-1 stereoselectively catalyzes the conversion of the l-phenylalanine into trans-cinnamic acid and ammonia, and was used in chiral resolution of dl-phenylalanine to produce the d-phenylalanine under acidic condition. However, the optimum pH of RgPAL is 9 and the RgPAL exhibits low catalytic efficiency at acidic side. Therefore, a mu...

We report the chiral diene ligated rhodium-catalyzed dynamic kinetic asymmetric transformation (DYKAT) of racemic secondary allylic trichloroacetimidates with a variety of N-methyl anilines, providing allylic N-methyl arylamines in high yields, regioselectivity, and enantiomeric excess. The rhodium-catalyzed DYKAT method addresses limitations previously associated with this particular class of ...

Kanemite was readily prepared and used as solid base catalyst for transesterification of sunflower oil to fatty acid methyl ester (FAME). The catalyst was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), N2 adsorption-desorption and field emission scanning electron microscopy (FESEM) techniques. Central Composite Design (CCD) coupled with Response Surfac...

Plants of the genus Taraxacum Wigg., have long been used as medicinal herbs. A phytochemical investigation of the aerial parts of Taraxacum bessarabicum (Hornem.) Hand.-Mazz. subsp. bessarabicum (Hornem.) Hand.-Mazz. (Asteraceae) yielded two coumarins [esculetin (1), cichoriin (2)], three flavonoids [ luteolin (3), luteolin 7-O-β-D-glucoside (4), gossypetin (5)] and six phenolic acids and their...

SUMMARY One ,ig of phorbol myristate acetate, an active tumor promoting agent from croton oil, produces a severe, local vascular reaction in skin (ear) of CF1 and STS mice. The response is characterized by hyperemia and edema formation which can be quantitatively monitored by measuring uptake of circulating ‘251-labeled bovine serum albumin. Micro scopic detection of sites of endothelial inju...

Tetrahydrobiopterin [(6R)-5,6,7,8-tetrahydro-L-biopterin, H(4)biopterin] is one of several cofactors of nitric oxide synthases (EC 1.14.13.39). Here we compared the action of N(5)-substituted derivatives on recombinant rat neuronal nitric oxide synthase with their effects on dihydropteridine reductase (EC 1.6.99.7) and phenylalanine hydroxylase (EC 1.14.16.1),the well-studied classical H(4)biop...

An optically active helical poly(phenylacetylene) was synthesized by the copolymerization of phenylacetylenes bearing optically active hydroxy or ester groups obtained by the kinetic resolution of a racemic phenylacetylene with lipase; the helix-sense was inverted from one helix to another by the further chemical modification of the hydroxy groups with achiral bulky isocyanates or an acid chlor...