Enzymes transferases

Transferases. Enzymes which transfer a group, possibly a methyl group or a glycosyl group, from one compound to another. The name of the group transferred is usually in-... 

Soffers AEMF, Ploeman JHTM, Moonen MJH, Wobbes T, van Ommen B, Vervoort J, et al. Regioselectivity and quantitative structure-activity relationships for the conjugation of a series of fluoronitrobenzenes by purified glutathione S -transferase enzymes from rat and man. Chem Res Toxicol 1996 9 638-46. 

The antimicrobial action of ethambutol, like that of isoniazid, is specific for mycobacteria, suggesting a target in the unique components of the mycobacterial cell wall. Cells treated with ethambutol accumulate an isoprenoid intermediate, decaprenyl-arabinose which is the source ofarabinose in the arabinogalactan polymer. This suggests that ethambutol blocks assembly of the arabinogalactan through inhibition of an arabinosyl transferase enzyme. 

Stevenson, D.E. and Hubl, U. (1999) Optimization of /3-D-glucuronide synthesis using UDP-glucuronyl transferase Enzyme and Microbial Technology 24, 388-396. 

Of the purine nucleosides, dATP may be derivatized at its N-6 position using a long linker arm terminating in a detectable group without losing the ability to be enzymatically incorporated into DNA probes. By contrast, if modification is done at the C-8 position of purine bases, DNA polymerase cannot by used to add the labeled monomer to an existing strand. C-8 derivatives, however, can be added at the 3 terminal using terminal transferase enzyme. 

Figure 27.1 Three common nucleoside triphosphate derivatives that can be incorporated into oligonucleotides by enzymatic means. The first two are biotin derivatives of pyrimidine and purine bases, respectively, that can be added to an existing DNA strand using either polymerase or terminal transferase enzymes. Modification of DNA with these nucleosides results in a probe detectable with labeled avidin or streptavidin conjugates. The third nucleoside triphosphate derivative contains an amine group that can be added to DNA using terminal transferase. The modified oligonucleotide then can be labeled with amine-reactive bioconjugation reagents to create a detectable probe.

In contrast to the other three cations, Mg2+ has a much slower exchange rate of water in its hydration sphere (Table 10.1). Mg2+ often participates in structures, for example in ATP-binding catalytic pockets of kinases and other phosphoryl-transferase enzymes, where... 

A catalytic effect that may be of the same type as the mimicry of acyl transferase enzymes is reported by Gandour et al. (1978). They describe the rate enhancement of the aminolysis of p-nitrophenyl acetate in the presence of bis(2,6-pyridinyl) crown ethers [328] and [329] in chlorobenzene. The rate of... 

Transferases. Enzymes that catalyse the transfer of specific groupings. 

How are the differential patterns of methylation in the imprinted alleles established and maintained Some evidence exists that differential methylation at the paternal and maternal imprinted alleles are established independently. Knockout of Dnmt3L, a protein that shares homology with de novo DNA methyl-transferase enzymes but does not possess methyltransferase activity, results in a complete loss of the maternally imprinted DNA methylation marks [57,58]. The precise mechanisms by which the paternal methylation imprints are established are yet to be determined. 

Ethambutol is a water-soluble, heat-stable compound that acts by inhibition of arabinosyl transferase enzymes that are involved in cell wall biosynthesis. Nearly all strains of M tuberculosis and M. kansasii and most strains of Mycobacterium avium-intracellulare are sensitive to ethambutol. Drug resistance relates to point mutations in the gene (EmbB) that encodes the arabinosyl transferases that are involved in mycobacterial cell wall synthesis. 

Hepatocellular changes at all dose levels, including histopathology and altered activities of glutathione S-transferase enzymes Acute oral LD50... 

Recognition of the glycosyl-donor structure by the transferase enzyme also shows high specificity. 

Structures of several important aminoglycoside antibiotics. Ring II is 2-deoxystreptamine. The resemblance between kanamycin and amikacin and between gentamicin, netilmicin, and tobramycin can be seen. The circled numerals on the kanamycin molecule indicate points of attack of plasmid-mediated bacterial transferase enzymes that can inactivate this drug. , , and , acetyltransferase , phosphotransferase , adenylyltransferase. Amikacin is resistant to modification at , , , and . 

In the classical form of galactosemia, there is a deficiency of uridyl-transferase enzyme resulting in galactouria, cataracts, and metabolic... 

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