In order to obtain the bifunctional chimeric molecule of single-chain urokinase-type plasminogen activator (scu-PA) which can inhibit platelet aggregation, PRGDWR peptide was inserted into the site between Gly 118 and Leu119 (called insertion mutant B, InB). The recombinant gene of InB was expressed by Pichia pastoris. The secreted protein was purified by metal chelate affinity and strong cation exchange chromatography. The amidolytic ability of mutant InB is 5 900 IU/mg, the kinetic constants is: KInB m,plg=56.8 μmol*L-1，kInBcat,plg=0.33 s- 1. The kinetic constants of plasminogen activation reaction is: KInB m,plg=0.397 μmol*L-1，kInBcat,plg=0.0164 s-1. Fibrin inhibit the catalytiv ability of InB during plasminogen activatio n, the influence factor is 0.463(means InB remain 46.3% of the catalytic abili ty when fibrin was involved in the reaction system). The mutant not only has alm ost the same catalytic ability as wild type scu-PA, but also has strong ability of anti-platelet aggregation(compared with scu-PA), IC50 of InB is 12.7 μmol*L-1.

Because the influence of fibrin on the reaction of plasm inogen activation by various plasminogen activators is different, the kinetic co nstant of the reaction of plasminogen activation catalyzed by InB with and witho ut fibrin were detected. The result is: Kfibrinm＝4.2 μmol*L -1，greater than the normal Km=0.379 μmol*L-1; kfib rincat＝0.107 s-1，greater than the normal kcat=0.0165 s-1. The results suggest that existence of fibrin in the reaction system of plasminogen activation depress the affinity between InB and plasminog en, but accelerates the hydrolysis of plasminogen by InB. The count up effect is inhibition.

When Playmonas cardiformis is exposed to different ZnSO4 concentration, its growth rate decreases gradually with the increase of ZnSO4 concentration which is more than 1 mmol?L~-1. More than 8 mmol?L~-1 ZnSO4 can lead to the death of playmonas subcordi- formis. But the production of MT-like increases with the increase of ZnSO4 concentration by AAS determination. The effect of indution is remarkable. The production of MT-like reaches 2. 1ing per gram wet weight when the concentration of ZnSO4 is 1 mmol?L~-1.

Objective: To study the effect of recombinant human intestinal trefoil factor ( rhITF) on the healing of rat chronic gastric ulcer , protect gastric mucosal and mechanisms are involved. Methods: (1) Acute gastric mucosal injury was induced by ethanol, stress, aspirin and pylorusl ligation. The injury index ,MDA, GMBL,hexosamine (Hex) and acid output were measure. (2) Chronic gastric ulcer was induced in rats by application of 50% glacial acetic acid to the serosa of the glandular stomach. After injury, rats received by rhITF or vehicle orally twice daily for 11 days. On day 12, gastric mucosal blood flow(GMBF)was measured under ether anesthesia. Then the pylorus was ligated for 3 hours and each stomach removed. The gastric acid output, ulcer index, Hex and nitric oxide(NO) content in gastric mucosa, as well as iNOSmRNA in the ulcer bed were determined. Results: (1) rhITF protected gastric mucosa from the acute lesion, and increased Hex content in gastric mucosa. (2) rhITF treatment significantly decreased the ulcer index and gastric acid output, but increased the GMBF, Hex and NO content in comparison with the control groups. In addition, rhITF also stimulated iNOSmRNA expression in the ulcer bed by situ hybridization analysis. Conclusion: rhITF can protect gastric mucosa against acute lesion, and enhance the healing of chronic gastric ulcer in the rats.This action may result from the inhibition of gastric acid output, increase of GMBF.Hex and NO content and rhITF stimulated iNOSmRNA expression.

Objective: To explore the effect of transgenic metallothionein (MT) mushroom on anti-radiation ability of mice. Method: Dried power of transgenic MT mushroom was mixed into the feed of ICR mice. After being fed for 23 d, they were irradiated by 5.0Gy 60Co-?rays. Then their anti-radiation ability was determined after being fed 7 d again. Results: Transgenic MT mushroom can evidently alleviate the injury of platelet and spleen induced by radiation, and apparently increase SOD activity and reduce MDA content in irradiated mice’s serum. Conclusion: Transgenic MT mushroom can improve anti-oxidation ability of irradiated mice.