Synthesis, Characterization And PTPs Inhibitory Activity Study Of Triazole Schiff Base And "Organic Claw" Polycarboxylic Copper Complexes

Protein tyrosine phosphatases (PTPs), in coordination with protein tyrosine kinases (PTKs), are crucial control mechanism in signal transduction pathways. Defective or inappropriate regulation of PTPs leads to abnormal physiological processes, including cancers, Alzheimer disease, immunodeficiency and diabetes. PTPs are therefore emerged as important targets of related disease. PTPs inhibitors especially the specific PTPs inhibitors toward individual PTP attract great interest, which are expected to be unique tools for evaluating the function of the enzymes as well as therapeutic drugs.One important type of PTPs inhibitors is metal complexes in which oxovanadium(IV) metal complexes have been more researched in past twenty years. PTPs inhibition is considered to be related to their effect of insulin mimics. Recently we find copper complexes are also potent PTP1B inhibitors and suggest copper complexes interfere with cell process by PTPs inhibition. Based on this work, two types of copper complexes are synthesized and characterized. Their inhibition abilities against five PTPs are evaluated. Main results were obtained as following:1. Seven copper complexes of Schiff base ligands containing 3,5-substituted-4-salicylideneamino-3,5-dimethyl-1,2,4-triazol and four dinuclear copper complexes of organic claw ligands (2,2’,2",2’"-(5-R-2-hydroxy-1,3-phenylene)bis(methylene)bis(azanetriyl)tetraacetic acid) have been synthesized and well characterized by element analysis, infrared spectra, thermo-gravimetric analysis, X-ray diffraction. The crystal structure information as following:Complex 1 and 2 were P-1 space group, and the crystallographic data a, b, c andα,β,γwere8.256(2), 7.7403(6)A; 11.907(2),8.7315(1)A; 14.242(3),15.534(2)A; 104.15(3), 102.878(2)°; 98.52(3),100.102(2)°and 97.03(3),101.399(1)°, rerespec- tively. Complexes 8 and 10 were P21/n space group, and the crystallographic data a, b, c andβwere 15.247(3),14.949(1)A; 10.892(2), 10.539(1)A; 18.678(3),15.143(1)A and 127.77(1),104.55(1)°, respecti-vely.2. The copper complexes containing 3,5-substituted-4-Salicyl-ideneamino-3,5-dimethyl-1,2,4-triazol potently inhibit PTP1B with IC50 of 0.038-0.091μM, which is stronger 3-4 fold than TCPTP and PTP-MEG2, and 3-9 fold than SHP-1. The four copper complexes of organic claw ligands exhibit almost same inhibition against PTP1B and SHP-1 with IC50 values ranging from 0.15-0.31μM, about 2-fold stronger inhibition than against PTP-MEG2,10-fold stronger inhibition than against TCPTP. It seems PTP inhibitory potency of copper complexes containing 3,5-substituted-4-Salicylideneamino-3,5-dimethyl-1,2,4-tria-zol is slightly stronger than copper complexes of organic claw ligands. Both of the two kinds of copper complexes almost do not inhibit SHP-2. The results demonstrate that copper complexes are potent PTPs inhibitors but have different inhibitory effect over different PTPs. Kinetic analysis indicates that they are reversible competitive inhibitors of PTP1B.3. Fluorescence titration studies suggest that the complexes bond to PTP1B with the formation of a 1:1 complex. The calculated value of kq (1.77×1014L·mol-1·s-1(complex 1),2.05×1014L·mol-1·s-1(complex 8)) was much greater than 2.0×1010 L·mol-1·s-1, indicating that the quenching mechanism of PTP1B by complex 1 was by static quenching interaction. The binding constants are over×106L·mol-1. The calculated thermo-dynamic parameters suggest hydrogen bonds, van der Waals andπ…πinteraction force in the binding.4. The electrochemistry behaviours of copper complexes with PTP1B were studied by CV. When PTP1B were added into the solution of copper complexes, the E1/2 of copper complexes were shifted negatively with the decreasing of peak current ip, This phenomenon indicates that the copper complexes interact with PTP1B. 5. Hemoglobin (Hb) in the hyaluronic acid (HA) was cast at pyrolytic graphite (PG) electrodes for researching its electrochemical and electrocatalytic properties. By cyclic voltammetry and square wave voltammetry, the formal potential E1/2 was-0.36 V and electron transfer rate constant (ks) of Hb on HA films was 5.19s-1. UV-Vis absorption spectra showed that the protein on HA film retained near-native secondary structure. The stable Hb-HA/PG gave analytically useful electrochemical catalytic responses to hydrogen peroxide.