The apparent co-operative effect of acetyl-CoA on this enzyme from different sources has been shown by various authors [l, 3-101. Although this enzyme is known to be found in appreciable quantities only in the liver and the kidney, hardly any attempt has been made to justify the inter-relationship between the positive effecters acetyl-CoA and Mg2+ in this enzyme system. Furthermore, it is also ...

We have investigated the interaction of divalent ions with chromatin towards a closer understanding of the role of metal ions in the cell nucleus. The first row transition metal ion chlorides MnCl2, CoCl2, NiCl2 and CuCl2 lead to precipitation of chicken erythrocyte chromatin at a significantly lower concentration than the alkali earth metal chlorides MgCl2, CaCl2 and BaCl2. A similar distincti...

The sorption kinetics of the divalent metals Zn, Co, Ni, and Cd to hematite were studied in single sorbate systems with high sorbate/sorbent ratios (from 1.67 to 3.33mol sorbate/mol sorption sites) in 10mM Na-piperazine N,N'-bis 2-ethane sulfonic acid (Na-PIPES) solution at pH 6.8. The experimental data showed a rapid initial sorption (half-time about 1min) followed by slower sorption that cont...

In a combined experimental and theoretical study, we show that capacitive charging of porous electrodes in multicomponent electrolytes may lead to the phenomenon of time-dependent ion selectivity of the electrical double layers (EDLs) in the electrodes. This effect is found in experiments on capacitive deionization of water containing NaCl/CaCl(2) mixtures, when the concentration of Na(+) ions ...

Background: Heavy metals in aquatic systems usually interfere with many beneficial uses of water. Divalent nickel is a commonly occurring toxic metal in natural ecosystems due to the effluent of refineries, electroplating, and casting industries. In aquatic environments, nickel appears as Ni (II) and Ni0. Despite the high reported toxicity for Ni (II), Ni0 is only slightly toxic. Various meth...

A series of dinuclear complexes of a pseudocalixarene macrocycle H6L containing two 2,2'-methylenediphenol groups have been synthesised and structurally characterised. Using divalent metal ions, complexes containing a common hyperbolic paraboloid (saddle) M2(H4L)2+ core are formed. The structure is controlled by two strong O-H-O interactions resulting from metal ion-promoted monodeprotonation o...

Divalent ion sensitivity of hammerhead ribozymes is significantly reduced when the RNA structure includes appropriate tertiary stabilization. Therefore, we investigated the activity of the tertiary stabilized "RzB" hammerhead ribozyme in several nondivalent ions. Ribozyme RzB is active in spermidine and Na(+) alone, although the cleavage rates are reduced by more than 1,000-fold relative to the...

n-acetyl-b-d-glucosaminidase was purified by affinity and ionexchange chromatography. two major, a and b, and three minor intermediate forms were isolated and characterized. nag-a and nag-b were purified 440 and 1200 fold with final yields of 16 and 23 percent respectively. each activity was represented by a single protein band. after 70 min preincubation at 55°c a loss of70% activity of nag-a ...

Some new complexes of thiacetazone (Thz) and quinalizarin (Qz) with Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II) were prepared. The ligands and their metal complexes were characterized by phisco-chemical spectroscopic techniques. The spectral data suggested that the thiacetazone as a neutral bidentate ligand is coordinated with the metal ions through the N and S atoms. The ...

A semiconductor to metal transition (SMT) occurs either as a function of composition or external pressure in the TmSe-TmTe and TmSe-EuSe pseudobinary com ounds. The transition is caused by the delocalization of electrons from the 4flq shell of divalent Tm into the 5d conduction band. The divalent configuration (4f7) of the Eu ions is more stable and therefore is not involved in the SMT. A strik...