Reactivity of some transition metal complexes toward glutathione in the absence and presence of isolated and purified glutathione S-transferase. +CD

number: 
1357
إنجليزية
Degree: 
Imprint: 
Biotechnology
Author: 
Zahraa Farman Ameen
Supervisor: 
Dr. Ayad H. Jassim;
Dr. Essam F. Al-Jumaily,
year: 
2006
Abstract:

A new set of Schiff bases have been prepared in this work, which include:
2-[(cyclohexylimino)methyl]phenol(L1)N[4(diethylamino)benzylidene]-N-(4-thoxyphenyl)amine(L2) 1-[(4-methoxyphenyl)imino)methyl]-2-naphthol (L3), along with their complexes, with Pt(IV), Au(III), Pd(II) and Cu(II) metal ions. All the Schiff bases and their metal complexes have been characterized using FT.IR, UV-Vis. Spectroscopy, CHN-elemental analysis, Magnetic Susceptibility, and Conductivity measurements. The following formula for the prepared complexes can be suggested: [Mk(L1)n(L')m]X for Pt(IV) k=1, n = 1, L' = Cl , m = 4, X = 0 for Au(III) k=1, n = 1, L' = Cl , m = 2, X = 0 for Pd(II) k=1, n = 2, L' = 0 , m = 0, X = 0 for Cu(II) k=2, n = 8, L' = ONO2 , m = 2, X = 0

[Mk(L2)n(L')m(L'')t]X for Pt(IV) k=2, n = 4, L' = Cl, m = 6, L''=0, t=0, X = Cl
for Au(III) k=1, n = 6, L' = 0, m = 0, , L''=0, t=0, X = Cl for Pd(II) k=2, n = 4, L' = Cl, m = 4, L''=H2O, t=2, X = 0 for Cu(II) k=1, n = 3, L' = ONO2, m = 1, L''=H2O, t=2,
X=NO3

[Mk(L3)n(L')m]X for Pt(IV) k=1, n = 2, L' = Cl , m = 2, X = Cl for Au(III) k=1, n = 2, L' = 0 , m = 0, X = Cl for Pd(II) k=2, n = 6, L' = 0 , m = 0, X = Cl for Cu(II) k=1, n = 2, L' = 0 , m = 0, X = 0

The Glutathione S-transferase was isolated from rat liver and purified follow three steps, i.e. Ion Exchange Chromatography (using DEAE-Cellulose, then CM-Cellulose), finally using Gel Filtration Chromatography using Sephacryl S-200. Electrophoresis technique was used to estimate the purity of the purified enzyme and to measure its molecular weight. The non-enzymatic and enzymatic reactivity's of eight of the prepared complexes toward glutathione were measured under physiological conditions (phosphate buffer 0.1M, pH=6.7, 30oC). 1-chloro 2,4-dinitrobenzene was used as standard substrate to assay the enzyme activity and for the comparative study of the conjugation reaction. The rate and rate constant of the conjugation reaction were calculated, the reactivity (as reflected by the k2 values) was found to follow the following sequence: L2Au > L3Au > L2Pd > L3Pd > L3Pt > L2Pt > CDNB > L2Cu > L3Cu It was found that most cationic complexes (L2Au, L3Au, L3Pd, L3Pt, L2Pt, and L2Cu) were of greater reactivity than neutral complexes (L2Pd, L3Cu) and those gold (III) complexes where of highest k2 values while copper (II) complexes having lowest values.