三价砷和五价砷对鱼类乙酰胆碱脂酶的体外抑制比较

为开展水产品中三价砷的酶法快速检测工作,文中研究了三价砷(As3 + )、五价砷(As5+ )对8种鱼脑中乙酰胆碱酯酶(AChE)的抑制率。结果发现,在10 -7～10 -4mol/L范围内,草鱼和鲫鱼脑中AChE的抑制率与三价砷的浓度负对数值有较好的线性关系,相关系数都在0 .97以上;在10 -6～10 -4mol/L范围内,黑、马鲛、鲈鱼脑中AChE的抑制率与三价砷的浓度负对数值的线性相关系数大于0 .99。对于三价砷,由IC50 得到AChE的敏感性为:美国红鱼>草鱼,鲫,鲈鱼>黑,马鲛>鲤,白鲢。鱼种不同,AChE受到的三价砷、五价砷的抑制作用也不同。在浓度为10 -6～10 -4mol/L范围内,三价砷、五价砷对8种鱼脑中AChE的抑制作用存在极显著差异(p <0 .0 1) ,三价砷对AChE的抑制作用远大于五价砷的抑制作用。

Comparative Study on the Inhibition of Arsenic and Arsenate to Brain Acetylcholinesterase from Different Fish Species

The inhibitory effects of trivalent arsenic(As 3+ ) and arsenate(As 5+ ) on brain acetylcholinesterase(AChE) from eight kinds of fishes were studied. It can be found that the AChE of Ctenopharyngodenidellus and Carassius auratus show a good dose-effect relationship with -log[As 3+ ]. When the concentration of As 3+ is in the range of 10 -4 mol/L to 10 -7 mol/L, the linear correlation coefficients are more than 0.97. The AChE of Sabasdotes fuscescens, Scomberomorus niphonius and lateolabrax japonicus also have a good linear correlation with -log[As 3+ ] when the concentration of As 3+ is from 10 -4 mol/L to 10 -6 mol/L(R>0.99). It can be concluded from the IC 50 values that the sensitive order of AChE to As 3+ is: sciaenops ocellatus> Ctenopharyngodenidellus, Carassius auratus, lateolabrax japonicus> Sabasdotes fuscescens, Scomberomorus niphonius> Cyprinus carpio, hypophthal michthys molitrix. the inhibitory rate was different with different fish species. When the concentration of inorganic arsenic is from 10 -6 mol/L to 10 -4 mol/L, great differences can be found between the inhibitory rates of As 3+ and As 5+ (p<0.01) for eight kinds of brain acetylcholinesterase. The inhibitory rate of As 3+ is far greater than that of As 5+ for AChE.