EHMO Studies of the Structures and Reactivities of Oxyhemocyanin and Oxytyrosinase Bimiclear Copper Active Sites

We have generated one possible active site structure of Oxyhemocyanin (Oxy-Hc) and two possible active site structures of Oxytyrosinase (Oxy-Ty) using the EHMO method. Oxy-Hc active site has a plane configuration, while Oxy-Ty has boat configuration. When there exist water molecules, two water molecules are connected with the Oxy-Ty active site weakly. Calculations for the reactions of Oxy-Hc and Oxy-Ty (the water-off) with phenol demonstrate that the former reaction is thermodynamically forbidden, while the latter Is realizable.

盐度升高对中华绒螯蟹几种非特异性免疫因子的影响

采用逐步增盐法,结合生物酶学测定,研究了从淡水升高盐度到7、14、21、28和35对二秋龄雌、雄中华绒螯蟹血清总蛋白、氧合血蓝蛋白含量及碱性磷酸酶(AKP)、超氧化物歧化酶(SOD)、酚氧化酶(PO)活力的影响。结果显示,随着盐度的升高,中华绒螯蟹的血清总蛋白、氧合血蓝蛋白含量逐渐降低;AKP活性先略升高,而后逐渐降低;与雄蟹的PO活力逐渐降低相比,雌蟹的PO活力先降低,当盐度高于21后维持稳定水平;SOD活性先略降低,盐度高于21被激活。除SOD外,雌蟹血清各测定指标均显著高于雄蟹(P<0.05)。研究结果表明,盐度接近或超过28将显著影响中华绒螯蟹3种免疫酶的活性及总蛋白和氧合血蓝蛋白的含量,进而影响其免疫防御能力。