previous studies have suggested that ketamine, an n-methyl-d-aspartate (nmda) receptor antagonist, provides a pre-emptive analgesic effect and pre-emptive analgesia improves postoperative pain management. the aim of this study was to determine the effict of pre-incisional vs. post-incisional intravenous low dose of racemic ketamine in postoperative pain in children undergoing inguinal hernia re...

Aspartame, l-aspartyl-l-phenylalanine methyl ester, has two hydrates (IA and IB), a hemi-hydrate (IIA) and an anhydrate (IIB). The hydration/dehydration behavior of aspartame was investigated using hot-humidity stage X-ray powder diffraction (XRPD) and molecular mechanics modeling in combination with differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The results of th...

Human fibroblast interferon binds to L-tryptophan, D-tryptophan, L-phenylalanine, and L-tyrosine, all immobilized directly to cyanogen bromide-activated agarose, as well as to L-tryptophan and D-tryptophan methyl ester, both immobilized via molecular arms. The retention of fibroblast interferon is selective and results in a 2300-fold purification. Human leukocyte interferon binds neither to L-t...

Brown pigment(s) formed in Cryptococcus neoformans when grown on media containing extracts of the seeds of Guizotia abyssinica cannot be extracted by common organic solvents or by 6 n HCl or 2 n NaOH. A similar pigmentation was observed in C. neoformans when grown on a medium containing caffeic acid isolated from the hydrolyzed methanol extract of G. abyssinica seeds. Its methyl ester and the d...

We present the first report of enzymatic catalysis in an ionic liquid. The virtually nonexistent vapor pressure makes ionic liquids an exciting new alternative for enzyme-catalyzed syntheses in environmentally friendly environments. Z-aspartame was synthesized in a thermolysin-catalyzed reaction of carbobenzoxy-L-aspartate and L-phenylalanine methyl ester hydrochloride in 1-butyl-3-methylimidaz...

We have isolated glutamic acid 5-methyl ester from an Escherichia coli protein that is involved in chemotaxis. The bacteria were first incubated with [methyl-3H]methionine under conditions which are known to result in methylation of the protein. The protein, isolated by gel electrophoresis, was then digested by successive treatment with three proteolytic enzymes. One of the products was [methyl...

One of the most attractive hypothesis for the origin of homochirality in terrestrial bioorganic compounds is that a kind of "chiral impulse" as an asymmetric excitation source induced asymmetric reactions on the surfaces of such materials such as meteorites or interstellar dusts prior to the existence of terrestrial life (Cosmic Scenario). To experimentally introduce chiral structure into racem...

The crystal structure of para-methyl-l-phenylalanine at 230 K resembles that of the para-fluorinated analogue from the literature but is commensurately modulated with seven molecules in the asymmetric unit (Z' = 7). At 100 K, the superstructure loses its modulation, leading to a unit cell with Z' = 1, with clear disorder in the phenyl ring orientations. The methyl-substituent in para-methyl-l-p...

Laccase activity and stability were improved and modified through the interaction between laccase amino acid residues (e.g., amino groups (NH2) and carboxyl groups (-COOH)) and the chemical reagents thiourea dioxide (TDO) and L-phenylalanine methyl ester hydrochloride (L-PME). Compared with the control sample, the activity of the laccase modified with these chemical reagents was increased by 20...

BACKGROUND Aspartame (L-phenylalanine N-L-alpha-aspartyl-1-methyl ester) is an artificial sweetener with widespread applications. Previously published results have shown that among rats receiving aspartame a significant increase of lymphoreticular neoplasms, brain tumours and transitional cell tumours occurred. The aim of our short-term experiment was to investigate the biological effect of asp...