Detail of "2742-27-0"

Reference

The pH dependence of the active-site serine DD-peptidase of Streptomyces R61

The pH dependence of the active-site serine DD-peptidase of Streptomyces R61. Varetto, Louis; Frere, Jean Marie; Nguyen-Disteche, Martine; Ghuysen, Jean Marie; Houssier, Claude (Inst. Chim., Univ. Liege, Sart-Tilman B-4000, Belg.). Eur. J. Biochem.Some commonly used reagents like 107316-79-0 is used in this experiment., 162(3), 525-31 (English) 1987. CODEN: EJBCAI. ISSN: 0014-2956. DOCUMENT TYPE: Journal CA Section: 7 (Enzymes) Titrn. of the active site serine DD-peptidase of Streptomyces R61 shows that formation of acyl enzyme during hydrolysis of the substrate Ac2-L-Lys-D-Ala-D-Ala and enzyme inactivation by the b-lactam compds. benzylpenicillin, N-acetylampicillin, and ampicillin relies on the acidic form of an enzyme's group of pK ~9.5. It is proposed that protonation of a lysine e-NH2 group facilitates initial binding by charge pairing with the free CO2H of the substrate and the b-lactam mols. Lowering the pH from 7 to 5 has no effect on the 2nd-order rate const. of enzyme acylation by benzylpenicillin and N-acetylampicillin, but results in a decreased rate const. of acylation by ampicillin and Ac2-L-Lys-D-Ala-D-Ala. Protonation of the side chain NH2 group of ampicillin and a decreased efficacy of the initial binding of the peptide to the enzyme seem to be responsible for the obsd. effects. Whatever the mol. bound to the enzyme, there is no sign for the active involvement of an enzyme histidine residue of pK 6.5-7.0 in the hydrolysis pathway. .

Synthesis of isotope-labeled 14C-benzo[a]pyrene

Synthesis of isotope-labeled 14C-benzo[a]pyrene. Devdariani, T.Several substances are used for example 89595-99-3 and 2742-27-0 which are their cas registry numbers. V. (USSR). Metody Biokhim. Issled. Rast., Tbilisi, 119-22 From: Ref. Zh., Khim. 1983, Abstr. No. 20Zh172(Russian) 1983. DOCUMENT TYPE: Journal CA Section: 25 (Benzene, Its Derivatives, and Condensed Benzenoid Compounds) Title only translated. .