眼镜王蛇(Ophiophagus hannah)中L-氨基酸氧化酶(LAO)的纯化及某些理化性质和酶学性质的研究

本文报道了眼镜王蛇毒中LAO的纯化及某些性质,从眼镜王蛇毒中所分离的LAO在比活力、酶学性质及同工酶谱方面与从其他蛇毒来源的LAO存在显著不同. 聚丙烯酰胺凝胶电泳显示该酶是均一的.由梯度聚丙烯酰胺凝胶电泳测得全酶分子量约为1.5×105.SDS梯度聚丙烯酰胺凝胶测得亚基分子量为7.3×104.表明该酶是由二个分子量相同的亚基组成.吸收光谱显示每个分子含二个FAD. 酶氧化L-丙氨酸的最适pH为8.7—9.0.当底物浓度大于3n M时,出现明显产物抑制.该酶具有一定热稳定性,在55℃以下加热40分钟对酶活力基本无影响,当酶的浓度低于5.7微克/毫升时酶的浓度和酶反应速率呈线性关系.     

排水管网结构系统的优化设计

将地势———地貌用于排水系统优化设计 ,利用地势———地貌、排水规划及城市街道形成有向网络图 ,将网络中线段赋予了管线造价匹配权 ,讨论了直接法在有向网络图优化中作用 ,分析了计算赋权有向网络的Dijkstra算法及其过程 ,结合工程实际给出了计算结果。     

ISOLATION AND PROPERTIES OF L-AMINO ACID OXIDASE FROM OPHIOPHAGUS HANNAH VENOM

This paper reports the isolation and some properties of L-amino acid oxidase from Ophi-ophagus hannah venom. The differences between L-amino acid oxidase from Ophiophagusohannah and that from other sources in specific activity, properties and the spectrum of iso-zymes are noticeable. The result of electrophoresis on polyacrylamide gel shows that this purified enzyme ishomogenous. The molecular weight determined by gradient polyacrylamide gel slab (4--30%)is around 15×10~4 dalton. The molecular weight of the subunit determined by SDS gradient gelelectrephoresis (4--30%) is around 7.3×10~4 dalton. Therefore, this enzyme is composed of twosubunits. The absorption spectrum reveals that there are two FADs in each molecule. The optimum pH of enzymic reaction is around 8.7--9.0 when L-leucine is used as substrate.The inhibition of the preducts is noticeable when substrate concentration goes beyond 3mM.This enzyme is heat stable and its activity would not decrease obviously after heating at 55℃for 40 min. A linear relationship between enzyme concentration and reaction rate was noticedwhen enzyme concentration was below 5.7μg/ml.