重金屬對於人類紅血球過氧化氫酶活性的影響

先前有文獻提到因為工業、農業和人為活動等引起的重金屬污染對魚類會產生氧化性壓力，並且指出魚類體內的過氧化氫酶活性可以作為魚類發生有害的氧化性壓力之前的一個靈敏的生物指標。由於除了魚類以外，人類也是一種依賴水的動物，因此發生在人類身上的重金屬危害時常可見。已知重金屬會導致氧化壓力、紅血球中過氧化氫酶(catalase；CAT)活性下降以及麩胱甘肽（Glutathione；GSH）含量下降。但是重金屬是否直接影響CAT活性尚不清楚。我們實驗室將人類紅血球CAT處理銅、鐵、鉛、鎘及鋅等重金屬離子，接著以CAT測定方法進行分析，發現5 mM及6 mM的鉛及鐵對人類紅血球細胞CAT活性有明顯的抑制效果，鉛的抑制常數(inhibition constant；Ki)為13.8146 mM。銅、鎘及鋅對人類紅血球細胞CAT活性則沒有明顯的抑制效果。可見，重金屬在高濃度才有直接抑制作用。

In previous studies, the heavy metal pollutions from industrial, agricultural and anthropogenic activities caused oxidative stress of fish. It also noted that catalase (CAT) activity is considered as a sensitive biomarker of oxidative stress before hazardous effects occur in fish. In addition, fish ,human are also living depend on the water. The heavy metal poisoning were easily find in human. The heavy metals were known to cause oxidative stress and decrease the CAT activity in red blood cell and the glutathione content. However, whether the CAT activity was affected directly by heavy metals still unknown. We treated the CAT from human red blood cell with the heavy metal ions of Cu+2, Fe+3, Pb+2, Cd+2 and Zn+2. As fellowed by CAT assay, we find that the concentrations of 5 mM and 6 mM of Pb+2 and Fe+3 have significant inhibition on CAT activity, the inhibition constant of lead was 13.8146 mM. But Cu+2 ,Cd+2 and Zn+2 has no significant inhibition on CAT activity. The heavy metal only directly inhibit the CAT activity in high concentrations.