RESUMEN
To find novel antihepatitis drugs, a series of nitrate-oleanolic acid (OA) hybrids (10a, 10b, 11a-11e and 12a-12c) were designed and synthesized on the basis of previous studies using OA as lead compound, which is widely found in natural plants and liver-specific metabolism. In the present study, ten novel NO-releasing derivatives of OA were synthesized by connecting nitrate to the OA-3-OH through varying lengths of linkers containing antioxidants which were designed to increase the ability of these target compounds to scavenge free radicals. The structures of these objective compounds were determined by IR, MS, 1H NMR and elemental analysis. Their protective effects on anti-Fas mediated HepG2 cell apoptosis were in vitro evaluated by LDH assay. Compound 12a is the most potent inhibitor. Its effect on anti-Fas mediated HepG2 cell apoptosis and amount of NO-releasing in vitro are similar to those of positive control NCX-1000.
RESUMEN
Utilizing higher expressing vector and a synthetic oligonucleotide linker,a new expressing clone, pBMhIL 4, has been constructed in our laboratory. The intact human rIL-4 protein molecule was expressed under the control of pL promoter in E. coli. The gene encoding protein was expressed in the plasma of E. coli in the form of inclusion bodies, the expressed IL-4 constituting about 5-10% of the total cellular proteins by SDS-PAGE analysis. The molecular weight of human rIL-4 was about 15KD. After extraction and renaturation, the yieldedsoluble human rIL-4 exhibited biological activity. 1?10~6 units of human IL-4 were produced from 1 liter of bacteria extracts assassed by the assay of its TCGF activity. Using 3.5M Guanidine hydrochloride and 0.25% Triton X100 to lyze inclusion bodies resulted in higher yield and higher biological activity.
RESUMEN
Utilizing Polmerase Chain Reaction (PCR) and recombination DNA techniques with synthetic oligonucleotide primers,a high level expressing clone for human IL- 6, pBMhIL6, was constructed successfully in our laboratory. The intact human rIL-6 protein molecular was expressed under the control of p_Rp_L promoters, synthetic SD sequence and the terminal codon TAA which replaced TAG of original human IL-6 in E. coli. the expressed human rIL-6 protein, molecular wight 21 KDa, with specific binding to Anti-IL-6 McAb, constituted about 28% of the total cellular proteins assessed by SDS-PAGE, densitometry analysis and Western Blot assay. The results of study on kinetics of inducing human rIL-6 expression in the defferent E. coli strains and influence of bacteria growth states ingdicate that the higher productive ratio for human rIL-6 inducing expression was obtainde in E. coli DH5a at O. D=0. 7. 5?10~6 unites of human rIL-6 HPGF bioactivities were produced from 1 litre of bacteria extracts assayed by 3HTdR uptake of 7TD1 cell line.