某些金属离子对黄斑鲶（鱼类，长须鲶科）血液和肝脏δ-氨基乙酰丙酸脱水酶的影响

Effect of some metal ions on blood and liver delta-aminolevulinate dehydratase of Pimelodus maculatus (Pisces, Pimelodidae).

Rodrigues A L, Bellinaso M L, Dick T

Departamento de Bioquímica e Centro de Ecologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brasil.

Comp Biochem Physiol B. 1989;94(1):65-9. doi: 10.1016/0305-0491(89)90012-6.

Abstract

delta-ALA-D from Pimelodus maculatus was inhibited in vitro by Cd2+ greater than Pb2+ greater than Hg2+ greater than Cu2+ greater than Zn2+ in blood and by Pb2+ greater than Cd2+ greater than Hg2+ greater than Cu2+ = Zn2+ in the liver. 2. Kinetic analysis of the inhibition by the metal ions showed that Cd2+ and Hg2+ act as non-competitive inhibitors on both sources. 3. Pb2+ showed a mixed type of inhibition in blood and a non-competitive type in the liver. 4. Zn2+ acted as a competitive or mixed inhibitor, on both sources, depending on concentration.

摘要

黄斑锯齿鲶血液中的δ-氨基乙酰丙酸脱水酶（delta-ALA-D）在体外受到镉离子（Cd2+）的抑制作用大于铅离子（Pb2+），大于汞离子（Hg2+），大于铜离子（Cu2+），大于锌离子（Zn2+）；而在肝脏中则是铅离子（Pb2+）的抑制作用大于镉离子（Cd2+），大于汞离子（Hg2+），大于铜离子（Cu2+） = 锌离子（Zn2+）。2. 金属离子抑制作用的动力学分析表明，镉离子（Cd2+）和汞离子（Hg2+）对两种来源的酶均表现为非竞争性抑制剂。3. 铅离子（Pb2+）在血液中表现为混合型抑制，在肝脏中表现为非竞争性抑制。4. 锌离子（Zn2+）对两种来源的酶表现为竞争性或混合型抑制剂，这取决于其浓度。