작두콩 추출물의 Urease 활성에 대한 수은이온의 저해 영향 및 존재여부 감별

초록

Urease has been used to detect the presence of heavy metal ions in aqueous solution because this enzyme is inactivated by heavy metals such as Hg (II), Pb (II). However, industrial application of the purified urease to detect heavy metal ions is restricted by high cost for production and enzyme stability. This prompted us to use the crude extract of Jack bean to detect heavy metal ions in water sample since Jack bean is well known to contain high urease activity. In this paper, we tried to determine the inhibition of the urease activity of Jack bean crude extract by five different heavy metal ions such as Pb (II), Ni (II), Cd (II), Cr (VI), and Hg (II). Among those metal ions tested, only Hg (II) inhibited significantly the urease activity of Jack bean crude extract at the level of 1 nM. Unlike the purified urease reported elsewhere, other heavy metal ions did not inhibit the enzyme activity of Jack bean extract even at 100 mM and showed no interference with the inhibitory effect of Hg (II) as well. Amount of protein in crude extract over 20 ng/ml was good enough to detect the inhibition of urease activity by Hg (II). These results demonstrated that the urease activity of Jack bean crude extract could be used as a cost-effective tool to detect specifically the presence of Hg (II) ion at very low level in the industrial waste.

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