DNA interaction of ruthenium(ii) complexes with imidazo[4,5-f][1,10]phenanthroline derivatives

The DNA interaction properties of four Ru(ii) complexes with imidazo[4,5-f][1,10]phenanthroline derivatives were investigated by spectral titration, gel electrophoresis (GAR), dynamic light scattering (DLS), zeta potential, atomic force microscopy (AFM), and transmission electron microscopy (TEM).

Axial coordination reactions with nitrogenous bases and determination of equilibrium constants for zinc tetraarylporphyrins containing four β,β′-fused butano and benzo groups in nonaqueous media

The axial coordination properties of six zinc tetraarylporphyrins with seven different nitrogenous bases were examined in CH2Cl2 for derivatives containing four [Formula: see text],[Formula: see text]-fused butano or benzo groups and the equilibrium constants (log[Formula: see text] determined using spectral titration methods. The examined compounds are represented as butano(YPh)4PorZn and benzo(YPh)4PorZn, where Por is the porphyrin dianion and Y is a CH3, H or Cl substituent on the para-position of each meso-phenyl ring of the macrocycle. The initial four-coordinate butano- and benzoporphyrins will axially bind one nitrogenous base to form five-coordinate derivatives in CH2Cl2 and this leads to a 4–22 nm red-shift of the Soret and Q bands. The log[Formula: see text] values range from 1.98 to 4.69 for butano(YPh)4PorZn and from 3.42 to 5.36 for benzo(YPh)4PorZn, with the exact value depending upon the meso and [Formula: see text]-substituents of the porphyrin and the conjugate acid dissociation constants (p[Formula: see text] of the nitrogenous base.

Raman spectral titration method: an informative technique for studying the complexation of uranyl with uranyl(vi)–DPA/oxalate systems as examples

Spectral titration method with Raman spectroscopy is a powerful method for studying the complexation of uranyl(vi) with various ligands.

The screening of the inhibitors of the human cytochrome P450(51) (CYP51A1): the plant and animal structural lanosterol's analogs

The cholesterol biosynthesis regulation is the important part of the hypercholesterolemia diseases therapy. The inhibition of the post-squalene cholesterol biosynthesis steps provide the alternative to classic statin therapy. Sterol-14a-demethylase (CYP51) is one of the hypothetical targets for it. In this work the screening of the ability to interact with human CYP51 (CYP51A1) for the nature low-weight compounds with steroid-like scaffold were performed by integration of the surface plasmon resonance biosensor and spectral titration methods. The results of the selection were 4 compounds (betulafolientriol, holothurin A, teasaponin, capsicoside A) witch had high affinity to the CYP51A1 active site. These data extend the range of compounds which may be used as specific inhibitors of CYP51 and give the permission to suggest the dynamic of the enzyme.

Spectrophotometric titration with cobalt(III) for the determination of accurate absorption coefficients of transferrins

A rapid and sensitive technique, involving difference spectral titration with cobalt(III), to measure the ϵ values of chicken ovotransferrin, human serum transferrin, the N-lobe of human transferrin and several single point mutants is reported. The resulting ϵ values were compared with the values calculated from the equation proposed by Pace, Vajdos, Fee, Grimsley and Gray [(1995) Protein Sci. 4, 2411–2423]. The titrations with cobalt feature sharp break-points and do not destroy the protein samples. The choice of buffer was found to be important, depending on the metal-binding avidity of the proteins. Cobalt titration should prove useful for studying the comparative metal-binding properties of transferrin and mutants of transferrin being generated by recombinant technology.