蓖麻蚕脂肪体精氨酸酶的分离纯化及其性质的研究

本文利用丙酮处理,硫酸铵沉淀,DEAE纤维素层析,Sephadex G-50凝胶过滤等步骤提纯了蓖麻蚕精氨酸酶。该酶由两个分子量80,000的亚基组成,等电点为5.3,并测定了氨基酸组成。动力学实验表明酶的K_m值为20m M,精氨酸代谢的产物鸟氨酸及脯氨酸对该酶有竞争性抑制作用,最适pH为9.0,Mn~( )为酶表现活力所必需。苯甲磺酰氟及巯基乙醇可能通过作用于酶活性基团和影响其高级结构而抑制该酶。此外,还将蓖麻蚕精氮酸酶与大鼠及鸡肝脏精氨酸酶进行了一些比较。     

PURIFICATION,CHARACTERIZATION AND STRUCTURE OF CM_2Ph_1,AN ANTIBACTERIAL PEPTIDE FROM Bombyx mori

Using HPLC we purified an antibacterial peptide named CM_2Ph_1 from the hemolymph ofpupae of silkworm (Bombyx mori) immunized with polyI:C. Amino acid composition analysisshowed that CM_2Ph_1 contained 16 kinds of amino acids. Its primary structure determined bythe automatic Edman degradation method is GNFFKDLEKMGQRVRDAVISAAPAVDTLAKA-KALGQ. Its C-terminal residue was assumed to be Gln with a blocking α-carboxylamide bycarboxypeptidases analysis. The purified CM_2Ph_1 was found to have inhibition effects invarying degrees on several bacterial strains. At a concentration of 0.35 μmol/L, CM_2Ph_1could inhibit the growth of 50% E. coli D31 strain. Some other antibacterial peptides were compared with CM_2Ph_1 in respect to their struc-tures and functions. Their homology was also discussed in this paper.     

家蚕抗菌肽CM_2Ph_1的分离、纯化、结构及其性质的研究

本文应用HPLC技术纯化家蚕蛹血淋巴以polyI:C诱导产生的一个抗菌肽CM_2Ph_1。氨基酸组成分析含16种氨基酸残基。自动Edman降解序列测定其一级结构为GNFFKDLEKMGQRVRDAVISAAPAVDTLAKAKALGQ。羧肽酶分析C-末端残基可能为α羧基酰胺化的Gln。纯化后的CM_2Ph_1对多种细菌有不同程度的抑制作用,浓度在0.35μmol/L时,能抑制50％大肠杆菌D31株的生长。本文也比较了CM_2Ph_1与其它几种抗菌肽在结构与功能方面的异同,并讨论了它们之间的同源性。     

PROPERTIES OF ARGINASE FROM FAT BODY OF PHILOSAMIA CYNTHIA RICINI AND REGULATORY EFFECTS OF INSECT HORMONES ON ITS ACTION

Arginase as a widely occurring enzyme has been studied in various organisms and is endow-ed with different functional properties. In higher animals it is the key enzyme in the ureacycle. In birds, reptiles and fishes, arginase seems to have different metabolic roles. Ininsects as well as birds which have been known to be uricotelic, whether there exists a ureacycle is still controversial. However, the metabolic patterns of approximately millionspecies of insects with their varied living environments must be ertremely varied.