Mechanistic aspects of uncatalyzed and ruthenium(III) catalyzed oxidation of dl-ornithine monohydrochloride by silver(III) periodate complex in aqueous alkaline medium

The oxidation of an amino acid, dl-ornithine monohydrochloride (OMH) by diperiodatoargentate(III) (DPA) was carried out both in the absence and presence of ruthenium(III) catalyst in alkaline medium at 25 °C and a constant ionic strength of 0.10 mol dm⁻³ spectrophotometrically. The reaction was of first order in both catalyzed and uncatalyzed cases, with respect to [DPA] and was less than unit order in [OMH] and negative fraction in [alkali]. The order with respect to [OMH] changes from first order to zero order as the [OMH] increases. The order with respect to Ru(III) was unity. The uncatalyzed reaction in alkaline medium has been shown to proceed via a DPA-OMH complex, which decomposes in a rate determining step to give the products. Where as in catalyzed reaction, it has been shown to proceed via a Ru(III)-OMH complex, which further reacts with two molecules of DPA in a rate determining step to give the products. The reaction constants involved in the different steps of the mechanisms were calculated for both the reactions. The catalytic constant (K_Cat.const.) was also calculated for catalyzed reaction at different temperatures. The activation parameters with respect to slow step of the mechanism and also the thermodynamic quantities were determined.     

Reactivity of some sugars and sugar phosphates towards gold(III) in sodium acetate-acetic acid buffer medium

The kinetics of the oxidation of some aldoses and aldose phosphates have been studied spectrophotometrically in sodium acetate-acetic acid buffer medium at different temperatures. The reactions are first order with respect to [Au(III)] and [substrate]. Both H+ and Cl- ions retard the reaction. The reactions appear to involve different gold(III) species, viz. AuCl4-, AuCl3(OH2) and AuCl3(OH)- . The results are interpreted in terms of the probable intermediate formation of free radicals and Au(II). Aldoses react with gold(III) in the order: triose > tetrose > pentose > hexose. The sugar phosphates react with gold(III) at a faster rate than the parent sugars except glucose-1-phosphate, which reacts at slower rates than glucose. A tentative reaction mechanism leading to the formation of products has been suggested.     

Kinetics and mechanism of the Ir(III)-catalyzed oxidation of xylose and maltose by potassium iodate in aqueous alkaline medium

For the first time, the Ir(III) catalysis of the iodate oxidation of xylose and maltose in aqueous alkaline medium has been investigated. The reactions exhibit first-order kinetics with respect to lower [IO(3)(-)] and [OH(-)] and show zero-order kinetics at their higher concentrations. Unity order at low concentrations of maltose becomes zero order at its higher concentrations, whereas zero-order kinetics with respect to [xylose] was observed throughout its variation. The reaction rate is found to be directly proportional to [Ir(III)] in the oxidation of both reducing sugars. Negligible effect of [Cl(-)] and nil effect of ionic strength (mu) on the rate of oxidation have also been noted. The species, [IrCl(3)(H(2)O)(2)OH](-) was ascertained as the reactive species of Ir(III) chloride for both the redox systems. Various activation parameters have been calculated. Formic acid and arabinonic acid for maltose and formic acid and threonic acid for xylose were identified as the main oxidation products of the reactions. Mechanisms consistent with the observed kinetic data and spectral evidence have been proposed for the oxidation of xylose and maltose.     

The role of membrane processes in Au(III) and Au(0) accumulation by bacteria

The role of structural and functional factors in the processes of the bacterial cell interaction with colloid Au (0) and ionic Au (III) states has been investigated. It is shown that the bacterial walls of Bacillus sp. 4368 aggregating with colloid gold contain glycoprotein with isoelectric point 11. Glycoprotein from cell walls indifferent to colloid gold strain (Bacillus subtilis 168) has pHiso = 5. At the same time the cells of both strains accumulate Au (III) introduced into a medium in the form of tetrachloroaurate. The process is energy-dependent because it is suppressed by azide, uncouplers of oxidative phosphorylation and dicyclohexyl carbodiimide (DCCD). The role of ATPase of Au (III) accumulation has been studied on Bacillus sp. 4368 plasma membrane vesicles. The ATPase activity is inhibited by 70, 50 and 35-50% by vanadate, DCCD and Au (III), respectively, but it does not change in the presence of dinitrophenol and NaN3. ATP but not ADP and AMP stimulated the Au (III) accumulation by membrane vesicles and prevents the inhibitory action of azide but neither of DNP or DCCD. In the energized state membrane vesicles link gold sol particles. It has been assumed that the Au (III) accumulation is associated with the functioning of transmembrane potential generators, the metal being localized on the membrane surface.     

Conformational stability of ferrocytochrome c. Electrostatic aspects of the oxidation by tris(1,10-phenanthroline)cobalt(III) at low ionic strength

At ionic strengths below 0.1 M the oxidation of horse ferrocytochrome c by tris(1,10-phenanthroline)cobalt (III) and tris(2,2'-bipyridine)cobalt(III) proceeds by a pathway which is independent of the transition metal complex concentration. Formation of an activated form of the protein appears to be rate limiting. The rate of oxidation decreases as the ionic strength increases. This dependence of the reaction rate on inert electrolyte concentration indicates that electrostatic association of anions under physiological ionic strength confers stability to the protein. The activated form of the protein, which reacts at least 10(4) times as fast as the predominant form, is thought to be a conformation of the reduced protein with an open heme crevice. Binding of the open form of ferrocytochrome c with the redox-inactive cationic transition metal complexes hexamminecobalt(III) and tris(1,10-phenanthroline)chromium(III) inhibits the oxidation by tris(1,10-phenanthroline)cobalt(III). Reactions of tris(1,10-phenanthroline)cobalt(III) with 4-carboxy-2,5-dinitrophenyllysine 13 and 72 ferrocytochromes c show no dependence on ionic strength. NMR studies at pH 7 demonstrate that ferricytochrome c is partly (15%) in the open conformation at low ionic strength. Furthermore, the interaction of redox-inert tris (1,10-phenanthroline)chromium(III) with ferricytochrome c under conditions identical to those of the kinetic studies demonstrates that the transition metal complex binds only to the open form of the protein. Titration with increasing amounts of tris(1,10-phenanthroline) chromium(III) shows changes in the NMR spectrum that are inconsistent with a single binding site.     

Adsorption of gold(III), platinum(IV) and palladium(II) onto glycine modified crosslinked chitosan resin

The adsorption of Au(III), Pt(IV) and Pd(II) onto glycine modified crosslinked chitosan resin (GMCCR) has been investigated. The parameters studied include the effects of pH, contact time, ionic strength and the initial metal ion concentrations by batch method. The optimal pH for the adsorption of Au(III), Pt(IV) and Pd(II) was found to range from 1.0 to 4.0 and the maximum uptake was obtained at pH 2.0 for Au(III), Pt(IV) and Pd(II). The results obtained from equilibrium adsorption studies are fitted in various adsorption models such as Langmuir and Freundlich and the model parameters have been evaluated. The maximum adsorption capacity of GMCCR for Au(III), Pt(IV) and Pd(II) was found to be 169.98, 122.47 and 120.39mg/g, respectively. The kinetic data was tested using pseudo-first-order and pseudo-second-order kinetic models and an intraparticle diffusion model. The correlation results suggested that the pseudo-second-order model was the best choice among all the kinetic models to describe the adsorption behavior of Au(III), Pt(IV) and Pd(II) onto GMCCR. Various concentrations of HCl, thiourea and thiourea-HCl solutions were used to desorb the adsorbed precious metal ions from GMCCR. It was found that 0.7M thiourea-2M HCl solution provided effectiveness of the desorption of Au(III), Pt(IV) and Pd(II) from GMCCR. The modification of glycine on crosslinked chitosan resin (CCR) was studied by Fourier transform infrared spectrometry (FTIR) and scanning electron microscopy (SEM).     

The kinetics and mechanisms of the reactions of iron(III) with quercetin and morin

The kinetics and mechanisms of the reactions of a pseudo-first order excess of iron(III) with the flavonoids quercetin and morin have been investigated in aqueous solution at 25 degrees C and an ionic strength of 0.5M. Mechanisms have been proposed which account satisfactorily for the kinetic data. The data are consistent with a mechanism in which the metal:ligand complex formed initially on reaction of iron(III) with the ligand subsequently decomposes through an electron transfer step. Morin forms a 1:1 metal:ligand complex while quercetin forms a 2:1 metal:ligand complex. Both ligands showed evidence for the involvement of the iron hydroxo dimer Fe2(OH)2(4+) in the complex formation reaction at the hydroxy-carbonyl moiety. The iron(III) assisted decomposition of the initial iron(III) complex formed was also investigated and the rate constants evaluated. Both the complex formation and subsequent electron transfer reactions of iron(III) with these ligands were monitored using UV-visible spectrophotometry. All of the suggested mechanisms and calculated rate constants are supported by calculations carried out using global analysis of time dependant spectra.     

Oxidation of d-fructose with vanadium(V): A kinetic approach

The kinetics of the oxidation of d-fructose with vanadium(V) in perchloric acid have been studied. The reaction is of first order with respect to the [Fructose], but the values of the rate constant increase slightly with increasing [V(V)]. In the range from 0.002–0.02m V(V), the inverse of the second-order rate constant is linearly related to the inverse of [V(V)]. Sodium hydrogensulfate and perchlorate accelerate the reaction, the effect of the former salt being greater. At a constant [H⁺] and ionic strength, the reaction is of first order with respect to [HSO₄⁻]. At constant ionic strength, the reaction is of third order with respect to [H⁺]. The activation parameters have been determined. The data obtained have been compared with those for simpler mono- and poly-hydric alcohols. A possible three-step mechanism involving CH bond fission and yielding glucosones as primary products has been suggested.     

Binding of the Mn(III) complex of meso-tetrakis (4-N-methyl-pyridiniumyl) porphyrin to DNA. Effect of ionic strength

Interactions of the water-soluble Mn(III) complex of meso-tetrakis (4-N-methyl-pyridiniumyl) porphyrin (Mn(III)TMPyP) with DNA in aqueous solutions at low (0.01 M) and high (0.2 M) ionic strengths have been studied by optical absorption, resonance light scattering (RLS) and 1H NMR spectroscopies. Optical absorption and RLS measurements have demonstrated that in DNA solutions at low ionic strength the Mn(III)TMPyP form aggregates, which are decomposed at DNA excess. At high ionic strength the aggregation was not observed. We explain this effect by assuming that upon increase in ionic strength, Mn(III) TMPyP dislocates from the DNA sites, which produces better conditions for the porphyrin aggregation, to sites where the aggregation is hindered. The 1H NMR data demonstrated that the aggregation observed at low ionic strength reduces the paramagnetism of Mn(III)TMPyP. This phenomenon was not observed at the high ionic strength in the absence of aggregation.     

Interaction of metal ions with nucleic acids and related compounds. II. Studies on Au(III)-nucleic acid system

The nature of interaction of Au(III) with nucleic acids was studied by using methods such as uv and ir spectrophotometry, viscometry, pH titrations, and melting-temperature measurements. Au(III) is found to interact slowly with nucleic acids over a period of several hours. The uv spectra of native calf-thymus DNA 9pH 5.6 acetate buffer containing (0.01M NaCIO₄) showed a shift in λ max to high wavelengths and an increase in optical density at 260 nm. There was a fourfold decrease in viscosity (expressed as η_sp/c). The reaction was faster at pH 4.0 and also with denatured DNA (pH 5.6) and whole yeast RNA (pH 5.6). The order of preference of Au(III) (as deduced from the time of completion of reaction) for the nucleic acids in RNA > denatured DNA > DNA. The reaction was found to be completely reversible with respect KCN. Infrared spectra of DNA-Au(III) complexes showed binding to both the phosphate and bases of DNA. The same conclusions were also arrived at by melting-temperature studies of Au(III)-DNA system. pH titrations showed liberation of two hydroxylions at r = 0.12 [r = moles of HAuCl₄ added per mole of DNA-(P)] and one hydrogen ion at r = 0.5. The probable binding sites could be N(1)/N(7) of adenine, N(7) and/or C(6)O of guanine, N(3) of cytosine and N(3) of thymine. DNAs differing in their (G = C)-contents [Clostridium perfingens DNA(G = C, 29%), salmon sperm DNA (G + C, 42%) and Micrococcus lysodeikticus DNA(G + C, 29%), salmon sperm DNA (G = C, 72%)] behaved differently toward Au(III). The hyperchromicity observed for DNAs differing in (G + C)-content and cyanide reversal titrations indicate selectivity toward ( A + T)-rich DNA at lw values of r. Chemical analysis and job's continuous variation studies indicated the existence of possible complexes above and below r = 1. The results indicate that Au(III) ions probably bind to hte phosphate group in the initial stages of the reaction, particularly at low values of r, and participation of the base interaction also increases. Cross-linking of the two strands by Au(III) may take place, but a complete collapse of the doulbe helix is not envisaged. It is probable that tilting of the bases or rotaiton of the bases around the glucosidic bond, resulting in a significant distrotion of the double helix, might take place due to binding of Au(III) to DNA.     

Bovine cardiac myosin subfragment 1. Transient kinetics of ATP hydrolysis

The kinetics of binding and hydrolysis of ATP by bovine cardiac myosin subfragment 1 has been reinvestigated. More than 90% of the total fluorescence amplitude associated with ATP hydrolysis occurs with an apparent second-order rate constant of 8.1 X 10(5) M-1 S-1 and a limiting rate constant of approximately 140 S-1 (100 mM KCl, 50 mM 1,3-bis-[tris(hydroxymethyl)methylamino]-propane, 10 mM MgCl2, pH 7.0, 20 degrees C); the remaining 10% occurs more slowly (approximately 1 S-1). The observed rate constants are independent of subfragment 1 concentration under pseudo first-order conditions for ATP with respect to protein. The fraction of protein which hydrolyzes ATP rapidly is not a function of the nucleotide or protein concentration and appears to be constant irrespective of ionic strength or temperature within the range studied (50-100 mM KCl, pH 7.0, 15-20 degrees C). These data are compared to that obtained previously using subfragment 1 prepared by a different method which showed ATP-dependent aggregation of two protein species.     

Role of bio-metal Fe(III) in anticancer behaviour of tamoxifen.

Physicochemical, microbial and pharmacological studies on Fe (III)--Tamoxifen complex have been carried out in solid and aqueous phases. On the basis of elemental analysis, polarographic studies, amperometric titrations and IR spectral studies the probable formula for the complex has been worked out to be 1:1, Fe(III)--Tamoxifen. A tentative structure has been suggested to the complex. The metal ligand interaction has been studied using polarographic method at 27 degrees +/- 1 degree C and at ionic strength of mu = 1.0 (KCl). Microbial studies on the complex was carried out against various pathogenic bacteria and fungi using Raper's method. Mouse sarcoma cell line 180 and Balb/C mice were used for the anticancer screening of solid complex, in vitro and in vivo, respectively. The results of microbial and pharmacological studies with the M:Drug complex revealed that the complex is more potent as compared to the pure drug as regards to its anticancer activity. As such Fe (III) Tamoxifen complex may be recommended to the therapeutic experts for its possible use as more potent anticancer drug.     

Pd(II)-catalysed and Hg(II)-co-catalysed oxidation of D-glucose and D-fructose by N-bromoacetamide in the presence of perchloric acid: a kinetic and mechanistic study

The kinetics of Pd(II)-catalysed and Hg(II)-co-catalysed oxidation of D-glucose (Glc) and D-fructose (Fru) by N-bromoacetamide (NBA) in the presence of perchloric acid using mercury(II) acetate as a scavenger for Br- ions have been studied. The results show first-order kinetics with respect to NBA at low concentrations, tending to zero order at high concentrations. First-order kinetics with respect to Pd(II) and inverse fractional order in Cl- ions throughout their variation have also been noted. The observed direct proportionality between the first-order rate constant (k1) and the reducing sugar concentration shows departure from the straight line only at very higher concentration of sugar. Addition of acetamide (NHA) decreases the first-order rate constant while the oxidation rate is not influenced by the change in the ionic strength (mu) of the medium. Variation of [Hg(OAc)2] shows a positive effect on the rate of reaction. The observed negative effect in H+ at lower concentrations tends to an insignificant effect at its higher concentrations. The first-order rate constant decreases with an increase in the dielectric constant of the medium. The various activation parameters have also been evaluated. The products of the reactions were identified as arabinonic acid and formic acid for both the hexoses. A plausible mechanism involving HOBr as the reactive oxidising species, Hg(II) as co-catalyst, and [PdCl3.S]-1 as the reactive Pd(II)-sugar complex in the rate-controlling step is proposed.     

Kinetics and mechanism of Ru(III) and Hg(II) co-catalyzed oxidation of D-galactose and D-ribose by N-bromoacetamide in perchloric acid

Kinetics of oxidation of reducing sugars D-galactose (Gal) and D-ribose (Rib) by N-bromoacetamide (NBA) in the presence of ruthenium(III) chloride as a homogeneous catalyst and in perchloric acid medium, using mercuric acetate as a scavenger for Br(minus sign) ions, as well as a co-catalyst, have been investigated. The kinetic results indicate that the first-order kinetics in NBA at lower concentrations tend towards zero order at its higher concentrations. The reactions follow identical kinetics, being first order in the [sugar] and [Ru(III)]. Inverse fractional order in [H(+)] and [acetamide] were observed. A positive effect of [Hg(OAc)(2)] and [Cl(minus sign)] was found, whereas a change in ionic strength (mu) has no effect on oxidation velocity. Formic acid and D-lyxonic acid (for Gal) and formic acid and L-erythronic acid (for Rib) were identified as main oxidation products of reactions. The various activation parameters have been computed and recorded. A suitable mechanism consistent with experimental findings has been proposed.     

Protein-bound adenosine 5'-triphosphate: properties of a key intermediate of the magnesium-dependent subfragment 1 adenosinetriphosphatase from rabbit skeletal muscle

The time course of formation and decay of protein-bound adenosine 5'-triphosphate (ATP) has been monitored during single turnovers of the myosin subfragment 1 ATPase with nonspectrophotometric techniques. The rate constant controlling the ATP cleavage step increases markedly with ionic strength, so that in low salt the protein--ATP complex is observed transiently at higher concentration than the protein-products complex. The kinetics of the ATP cleavage step in a single turnover of the actosubfragment 1 ATPase indicates that under appropriate conditions this step is partially rate limiting during overall steady-state ATPase activity. It follows that a binary subfragment 1-ATP complex is a significant component of the steady-state intermediate of the actosubfragment 1 ATPase. Transient kinetic studies of ATP and adenosine 5'-(3-thiotriphosphate) [ATP (gamma S)] binding show directly that a substrate-induced protein isomerization accompanies ligand binding. The rate constant of the isomerization is 170 s-1 at pH 7.0, 15 degrees C, and 0.01 M ionic strength. Under these conditions nucleotide binding appears to be accompanied by a protein fluorescence increase that is 50% of the increase associated with magnesium-dependent steady-state ATPase activity.     

Mechanistic aspects of uncatalysed and Os(VIII) catalysed oxidation of 5-flourouracil - An anticancer drug by alkaline diperiodatoargentate(III)

The oxidation of an anticancer drug 5-fluorouracil (5-FU) by diperiodatoargentate(III) (DPA) was carried out both in the absence and presence of osmium(VIII) catalyst in alkaline medium at 27 °C and a constant ionic strength of 0.20 mol dm⁻³ spectrophotometrically attached with HI-TECH SFA-12 stopped flow accessory. The oxidation products in both the cases were identified as fluoroketene and Ag(I). The stoichiometry is same in both cases, i.e., [5-FU]:[DPA] = 1:1. The reaction was of first order in both catalysed and uncatalysed cases, with respect to [DPA] and was less than unit order in [5-FU] and negative fraction in [alkali]. The order in Os(VIII) was unity. In both cases [Ag(H₃IO₆)₂]⁻ itself is the active species of DPA. The uncatalysed reaction in alkaline medium has been shown to proceed via a DPA-5-fluorouracil complex, which decomposes in a rate determining step to give the products. In catalysed reaction, it has been shown to proceed via a Os(VIII)-5-fluorouracil complex, which further reacts with one molecule of DPA in a rate determining step to give the products. The reaction constants involved in the different steps of the mechanisms were calculated for both the reactions. The catalytic constant (k_Cat.const.) was also calculated for catalysed reaction at different temperatures. The activation parameters with respect to slow step of the mechanisms were computed and discussed for both the cases. The thermodynamic quantities were also determined for both reactions.     

Adsorption of chromium(III) on lignin

In order to assess the possibility of using lignin to remove Cr(III) from waters, the adsorption of Cr(III) on lignin isolated from black liquor, a waste product of the paper industry, was investigated. The influences of pH, lignin dosage, contact time, ionic strength, Cr(III) concentration and other metals were investigated. The Cr(III) adsorption was strongly dependent on pH and adsorbent dosage, but independent of ionic strength and other metal ions. The adsorption kinetic data can be described well with pseudo-second-order model and the equilibrium data can be well fitted using Langmuir two-surface model with a maximum adsorption capacity of 17.97 mg/g. Cr(III) adsorption on lignin was mainly through the ion-exchange mechanism and formed inner-sphere complexes with lignin. Successful application in removing Cr(III) was achieved by using a real wastewater sample. This study indicates that lignin has the potential to become an effective and economical adsorbent for the removal of Cr(III) from wastewaters.     

Chromium(III) interactions with nucleotides. III

Some new derivatives of Cr(III) with 5′AMP, 5′ATP, 5′CMP, 5′GMP, 5′IMP and 5′UMP have been obtained by reaction of the starting complexes cis and trans-[Cr(en)₂Cl₂]Cl with the above nucleotides.The complexes were characterized by elemental analysis, conductivity, infrared and electronic spectroscopy, and EPR for the 5′UMP derivative.In all cases, chlorine has been substituted and one ethylenediamine eliminated. The interaction of Cr(III) with the nucleotide seems to occur through the phosphate group and additional interaction through the heterocyclic ring especially for the 5′GMP and 5′IMP derivatives.The 5′UMP complex seems to be a dimer and the other complexes are polymer.     

Interaction of La (III) and Tb (III) ions with purine nucleotides: evidence for metal chelation (N-7-M-PO3) and the effect of macrochelate formation on the nucleotide sugar conformation.

The interaction of the La (III) and Tb (III) ions with adenosine-5'-monophosphate (5'-AMP), guanosine-5'-monophosphate (5'-GMP), and 2'-deoxyguanosine-5'-monophosphate (5'-dGMP) anions with metal/nucleotide ratios of 1 and 2 has been studied in aqueous solution in acidic and neutral pHs. The solid complexes were isolated and characterized by Fourier transform ir and 1H-nmr spectroscopy. The lanthanide (III)-nucleotide complexes are polymeric in nature both in the solid and aqueous solutions. In the metal-nucleotide complexes isolated from acidic solution, the nucleotide binding is via the phosphate group (inner sphere) and an indirect metal-N-7 interaction (outer-sphere) with the adenine N-1 site protonated. In the complexes obtained from neutral solution, metal chelation through the N-7 and the PO3(2-) group is prevailing. In aqueous solution, an equilibrium between the inner and outer sphere metal-nucleotide interaction has been observed. The ribose moiety shows C2'-endo/anti pucker in the free AMP anion and in the lanthanide (III)-AMP complexes, whereas the GMP anion with C2'-endo/anti sugar conformation exhibits a mixture of the C2'-endo/anti and C3'-endo/anti sugar puckers in the lanthanide (III)-GMP salts. The deoxyribose has O4'-endo/anti sugar pucker in the free dGMP anion and a C3'-endo/anti, in the lanthanide (III)-dGMP complexes.     

Comparative serum albumin interactions and antitumor effects of Au(III) and Ga(III) ions

In the present study, interactions of Au(III) and Ga(III) ions on human serum albumin (HSA) were studied comparatively via spectroscopic and thermal analysis methods: UV–vis absorbance spectroscopy, fluorescence spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and isothermal titration calorimetry (ITC). The potential antitumor effects of these ions were studied on MCF-7 cells via Alamar blue assay. It was found that both Au(III) and Ga(III) ions can interact with HSA, however; Au(III) ions interact with HSA more favorably and with a higher affinity. FT-IR second derivative analysis results demonstrated that, high concentrations of both metal ions led to a considerable decrease in the α-helix content of HSA; while Au(III) led to around 5% of decrease in the α-helix content at 200 μM, it was around 1% for Ga(III) at the same concentration. Calorimetric analysis gave the binding kinetics of metal–HSA interactions; while the binding affinity (K_a) of Au(III)–HSA binding was around 3.87 × 10⁵ M⁻¹, it was around 9.68 × 10³ M⁻¹ for Ga(III)–HSA binding. Spectroscopy studies overall suggest that both metal ions have significant effects on the chemical structure of HSA, including the secondary structure alterations. Antitumor activity studies on MCF7 tumor cell line with both metal ions revealed that, Au(III) ions have a higher antiproliferative activity compared to Ga(III) ions.