恶性疟原虫：S-腺苷-L-甲硫氨酸脱羧酶。

Plasmodium falciparum: S-adenosyl-L-methionine decarboxylase.

作者信息

Rathaur S, Walter R D

出版信息

Exp Parasitol. 1987 Apr;63(2):227-32. doi: 10.1016/0014-4894(87)90165-2.

Abstract

Putrescine-dependent S-adenosyl-L-methionine decarboxylase has been detected in the malaria parasite Plasmodium falciparum. Mg2+ did not affect the enzyme activity. The apparent Km value of the plasmodial enzyme for adenosyl-methionine was found to be 33 microM. Methylglyoxal bis(guanylhydrazone) competitively inhibited the enzyme activity with respect to adenosylmethionine. The inhibition constant for methylglyoxal bis(guanylhydrazone) was determined to be 0.46 microM. Spermidine was the main polyamine detected in the parasite. There was significant decrease in the S-adenosyl-L-methionine decarboxylase activity when the infected erythrocytes were incubated with chloroquine and mefloquine for 2 hr at 1 and 10 microM, respectively. Since at similar concentrations these drugs did not directly affect the plasmodial enzyme activity, the interaction of these drugs with the polyamine biosynthesis remains unclear.

摘要

在疟原虫恶性疟原虫中已检测到腐胺依赖性S-腺苷-L-甲硫氨酸脱羧酶。镁离子不影响该酶的活性。发现疟原虫酶对腺苷甲硫氨酸的表观Km值为33微摩尔。甲基乙二醛双（胍腙）相对于腺苷甲硫氨酸竞争性抑制该酶的活性。甲基乙二醛双（胍腙）的抑制常数测定为0.46微摩尔。亚精胺是在该寄生虫中检测到的主要多胺。当感染的红细胞分别在1微摩尔和10微摩尔的浓度下与氯喹和甲氟喹一起孵育2小时时，S-腺苷-L-甲硫氨酸脱羧酶活性显著降低。由于在相似浓度下这些药物不直接影响疟原虫酶的活性，这些药物与多胺生物合成的相互作用仍不清楚。