Equilibrium and kinetic studies of ligand BMXD complexation with copper(II) and glycylglycine

Equilibrium studies of BMXD complexation with copper(II) and glycylglycine were performed by potentiometric and UV-visible titration. The equilibrium constants determined by potentiometry for the ternary system are: [LCu₂P³⁺]/[LCu₂⁴⁺][P⁻]=8.11(3), [LCu₂HP⁴⁺]/[LCu₂P³⁺][H⁺]=5.39(2), [LCu₂H₋₁P²⁺][H⁺]/[LCu₂P³⁺]=−6.33(2), [LCu₂(OH)H₋₁P⁺][H⁺]/[LCu₂H₋₁P²⁺]=−8.20(1) and [LCu₂(OH)₂HH₋₁P][H⁺]/[LCu₂(OH)H₋₁P⁻¹]=−10.33(3), which are in good agreement with the values determined by UV-visible titration. The species formed were confirmed by electrospray mass spectrometry. The association constants, determined by kinetic studies, for the association of the second molecule of glycylglycine with the LCu₂P complex, for two ionic media, are 1.29 (KCl) and 1.27 (KNO₃). These are in good agreement with the values determined by thermodynamic measurements 1.41 (KCl) and 1.26 (KNO₃).     

Normalization and weighting: the open challenge in LCA

The International Journal of Life Cycle Assessment -     

Peptide Chain Initiation in Bacteria,Mitochondria and Chloroplasts

Abstract

Ribosomes prepared from the bacterium Bacillus subtilis, from mitochondria of Neurospora crassa and from chloroplasts of Euglena gracilis carry out the ApUpG-dependent reactions for peptide chain initiation demonstrated for Escherichia coli ribosomes. Initiation factors functionally similar to those from E. coli appear to be present on the above reported ribosomal preparations. The activity of ribosomes washed with high concentrations of ammonium chloride may be restored by adding initiation factors prepared from E. coli.