Platinum complexes and pyruvate kinase activity.

The interaction of platinum complexes with bovine heart pyruvate kinase (PK) was studied by absorption, CD, fluorescence spectroscopy and enzymic activity test. Our results showed that activity of PK was reduced by cis-DDP and potassium tetrachloroplatinate in a time-and concentration dependent manner. Cis-DDP was less effective than K2PtCl4 in reducing PK activity.

Binuclear Rhodium(II) Complexes With Selective Antibacterial Activity.

Binuclear rhodium(II) complexes [Rh(2)Cl(2)(mu-OOCR)(2)(N-N)(2)] {R = H, Me; N-N = 2,2'-bipyridine (bpy), 1,10-phenanthroline (phen)} and [Rh(2)(mu-OOCR)(2)(N-N)(2)(H(2)O)(2)](RCOO)(2) (R = Me, Et;) have been synthesized and their structure and properties have been studied by electronic, IR and (1)H NMR spectroscopy. Antibacterial activity of these complexes against Escherichia coli and Staphylococcus aureus has been investigated. The most active antibacterial agents against E.

Interaction of tetra-mu-acetatodirhodium(II) with human serum albumin.

The interaction of Rh2(OAc)4 with human serum albumin (HSA) has been studied by absorption difference spectroscopy, CD spectroscopy, and quantitative precipitating HSA-antibody test. Our results demonstrate that this rhodium complex reacts easily with HSA at several ratios of reagents. The Rh atoms are coordinated to protein molecules via the imidazole rings of His residues.

Impact of K2PtCl4 on the structure of human serum albumin and its binding ability of heme and bilirubin.

Absorption, CD, gel-filtration chromatography, and immunological tests were used to evaluate the interactions of K2PtCl4 with human serum albumin. Multidentate coordination of Pt(II) to HSA causes distinct variations in the protein conformation including a considerable decrease of the helical structure. The high excess of Pt(II) ions leads to dimerization of the protein.

Influence of aspirin and iron(III) tetrasulfonated phthalocyanine on bilirubin binding by human serum albumin.

The interaction of bilirubin with aspirin-modified human serum albumin (HSA) and the influence of iron tetrasulfonated phthalocyanine on bilirubin binding by the native protein has been studied by difference spectroscopy and circular dichroism measurements. Spectroscopic studies of the systems containing bilirubin and aspirin-modified HSA compared to the analogous systems with the native protein have shown that selective acetylation of albumin at lysine 199 inhibits bilirubin binding by this protein. In both cases, interaction between bilirubin and albumin leads to complex formation at a molar ratio of ligand to protein of 2:1.

Structural studies of iron and cobalt tetrasulfonated phthalocyanine-globin complexes.

The structure of the complexes of iron and cobalt tetrasulfonated phthalocyanines with globin has been investigated by circular dichroism (CD), electron paramagnetic resonance (EPR) and polyacrylamide gel electrophoresis. Electrophoretic investigations and the molecular weight estimation indicates that the model complexes in the solutions are dimers. It is evident from the results of CD measurements that the incorporation of the iron or cobalt tetrasulfonated phthalocyanine into apohemoglobin significantly increases the helical structure of the protein and causes an appearance of the induced Soret and visible Cotton effects.

Complexes of metal phthalocyanines with globin as the models of heme proteins.

The reaction between iron and cobalt tetrasulfonated phthalocyanines and globin results in the formation of the green complexes, as has been proved by difference spectroscopy. Spectrophotometric titration data indicate the formation of those complexes at the molar ratio 1:1. The complexes of ferrous, ferric and cobaltous tetrasulfonated phthalocyanines with globin have been isolated from the reaction mixtures by separation on Sephadex G-50 and precipitation of the protein fractions with ammonium sulfate.