Acetylation in vitro

YM. Yang, et al, The controlhng biodegradation of chitosan fibers by N-acetylation in vitro and in vivo. Journal of Materials Science Materials in Medicine, 18 (11) 2117-2121,2007. 

An in vitro ensymatic synthesis of sucrose was carried out ia 1944 (5). A successful chemical synthesis was performed by Lemieux and Huber (6) ia 1953 from acetylated sugar precursors. However, the economics and chemical complexities of both processes make them unlikely sources of supply. 

Cefpimizole (51) appears to be less active in vitro than cefotaxime and cefoperazone and to have a somewhat narrower activity spectrum although some strains of Pseudomonas are susceptible. It is not orally active, but its performance in vivo appears superior to what would be expected from its in vitro data. Its synthesis begins by acylation of cephaloglycin (48) with the bis acid chloride of imidazole-4,5-dicarboxylic acid (49) to give amide 50. The acetyl moiety at C-3 of this intermediate is displaced with 4-pyridineethanesulfonic acid and sodium iodide to give cef-pimazole (51) [16]. 

Histone Acetylation. Figure 1 Histone acetylation is a posttranslational modification of lysine residues of histones. This modification is catalyzed by histone actyl transferases (HATs), which transfer an acetyl group (yellow) from acetyl-Coenzyme A onto the E-amino group of the lysine residue. Histone deacetylation is catalyzed by histone deacetylases (HDACs), which hydrolyze the lysine bound acetyl group. HDAC inhibitors like Trichostatin A (TSA) are known to inhibit the deacetylation reaction in vivo and in vitro. 

Neu5Ac2en 4, a micromolar inhibitor of influenza virus sialidase 4 x 10 M (A/N2)] (Holzer et al. 1993), was first identified as a very good inhibitor in the late 1960s (Meindl and Tuppy 1969). A series of C-5 modified Neu5Ac2en derivatives provided the first improved in vitro inhibitors compared with the parent compound 4. The replacement of the C-5 A-acetyl moiety with a A-trifluoroacetyl group resulted in the most potent inhibitor of this series, 2-deoxy-2,3-didehydro-A-trifluoroacetylneuraminic acid 10 [A] 8 x 10 M (A/Nl)] (Meindl et al. 1974). While these C-5 modified compounds were also very effective in cell culture assays (Palese et al. 1974a Palese and Compans 1976), none, including the parent... 

Partially deacetylated chitin, a cellulose-like biopolymer consisting predominantly of N-acetyl-D-glucosamine chains, in the form of films or crosslinked hydrogels has been used for the delivery of drugs (28,29). The suitability of chitin as a vehicle for the sustained release of drugs was examined using indomethacin and papaverine hydrochloride as model drugs (30). In vitro studies showed that over 80% of the indomethacin was released within 7 hr, whereas papaverine hydrochloride dissolved almost immediately. 

Thus pectins in muro contain most elements of the cable model but have additional features due to esterification (acetyl- as well as methyl-) and branching. The ionic junction zones are similar to those of calcium pectate gels in vitro but also contam methyl-esterified junctions, and most of the single chains probably have a relatively high degree of methyl-esterification. 

There is some evidence that auranofin may also be biologically de-acetylated during its absorption from the gut [58]. It is unfortunate that so many in vitro studies to determine possible mechanisms for the anti-arthritic activity of auranofin have not considered (tetra) desacetyl-auranofin as the first likely active metabolite, with its far greater hydrophilicity than the administered auranofin (which is only a pro-drug). 

Royleanone, horminone, and acetyl horminone isolated from the roots of Salvia officinalis L. abrogated the survival of colon carcinoma cell Caco-2 and human hepatoma cell HepG2, cultured in vitro with induction of DNA breaks (48). 

Production of acetate ester pheromone components utilizes an enzyme called acetyl-CoA fatty alcohol acetyltransferase that converts a fatty alcohol to an acetate ester. Therefore, alcohols could be utilized as substrates for both aldehyde and acetate ester formation. In some tortricids an in vitro enzyme assay was utilized to demonstrate specificity of the acetyltransferase for the Z isomer of ll-14 OH [66]. This specificity contributes to the final ratio of... 

The importance of protonated N-hydroxy arylamines as ultimate carcinogens has been suggested for some time (28,40,139). From studies on their reactivity with nucleic acids at different pH s (2,15,16,63,130,131), the pK for protonation of the N-hydroxy group appears to be between pH 5a and 6 thus, a significant proportion (1-10%) of the N-hydroxy derivative exists as the protonated form even under neutral conditions. This would account for the significant levels of covalent modification of DNA observed in vitro by reaction with N-hydroxy arylamines at neutral pH. Consequently, it has been proposed that in vivo formation of non-acetylated aryl... 

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