The pK(a) of (Asp(158))-CO(2)H of papain (EC 3.4.22.2) was determined as 2.8 by using 4-chloro-7-nitrobenzofurazan (Nbf-Cl) as a reactivity probe targeted on the thiolate anion component of the Cys(25)/His(159) nucleophilic-acid/base motif of the catalytic site. The possibility of using Nbf-Cl for this purpose was established by modelling the papain-Nbf-Cl Meisenheimer intermediate by using QUA...

The Escherichia coli uncA gene codes for the a subunit of the F1-sector of the membrane proton-ATPase. Mutations in this gene cause loss of ATPase and ATP synthesis activity and, in some instances, derangement of F1 structure. From three mutants (uncA401, uncA453, and uncA447), an F1 of normal size and subunit structure may be purified. In this work, purified soluble F1 from these three mutants...

CaMnO(3) and Ca(2)Mn(3)O(8) were synthesized and characterized by SEM, XRD, FTIR and BET. Both oxides showed oxygen evolution activity in the presence of oxone, cerium(IV) ammonium nitrate and H(2)O(2). Oxygen evolution from water during irradiation with visible light (λ > 400 nm) was also observed upon adding these manganese oxides to an aqueous solution containing tris(2,2'-bipyridyl) rutheni...

The title compound, [Au(C(18)H(27)ClN(3))(C(18)H(15)P)](NO(3))(2), is a coordination complex of gold(I) triphenyl-phosphine with the N atom in the quinoline ring of the common anti-malarial compound chloro-quine (CQ). The pendant diethyl-amino group of the CQ ligand was found to be protonated. The complex exhibits a nearly linear coordination geometry around the Au(I) atom [N-Au-P = 176.94 (6)°...

The detection of small quantities of nitrogen-containing compounds on paper chromatograms is a problem of long standing interest. The ninhydrin technique, first introduced by Consden, Gordon, and Martin (l), has partially solved this problem and has proven to be extremely valuable. However, the narrow range of compounds detected, the decreased sensitivity with increased molecular weight of pept...

The first step of the base-promoted decomposition of N-chloro,N-methylethanolamine in aqueous solution (CH3N(Cl)CH2CH2OH + HO- --> imine + Cl- + H2O (+ CH2O) --> amine + aldehyde) is investigated at the MP2/6-31++G(d,p) computing level. Solvation is included by using both a microsolvated model, in which two explicit water molecules simulate the specific solvent effects, and a hybrid cluster-con...

Earlier studies (Tamm et al., 1954; Tamm, 1954) showed that benzimidazole derivatives of very high inhibitory activity on influenza and mumps virus multiplication could be produced by multiple substitution of chlorine atoms in the benzenoid ring with ft-D-ribofuranose present at Ni in the imidazole ring. In subsequent reports (Tarm, 1955; Tamm, 1956) evidence was presented to show that the mode...

We report efficient syntheses of the clinical agent cladribine (2-chloro-2'-deoxyadenosine, CldAdo), which is the drug of choice against hairy-cell leukemia and other neoplasms, from 2'-deoxyguanosine. Treatment of 3',5'-di-O-acetyl- or benzoyl-2'-deoxyguanosine (1) with 2,4,6-triisopropyl- or 4-methylbenzenesulfonyl chloride gave high yields of the 6-O-arylsulfonyl derivatives 2 or 2'b. Deoxyc...

The crystal structures at room temperature of the N-chloro-N-(2,6-dichlorophenyl)-chloroacetamides 2 ,6 -Cl 2 C 6 H 3 NClCOCCl 3 (1) and 2 ,6 -C l 2 C 6 H 3 NClCOCH 2 Cl (2) have been determined. (1): or thorhombic , Pbca. Z = 8, a = 2051.7(8) pm, b= 1134.8(4) pm, c = 1089.0(4) pm. (2): orthorhombic, Pbca, Z = S, a = 2078.7 (4) pm, b= 1487.9(4) pm, c = 694.0 (2) pm. The " C I N Q R spectrum of ...