摘要
本文采用4-甲基伞形酮苯基磷酸酯为底物检测人血清中酶活性情况,发现在人血清中存在一种能够选择性水解苯基膦酸单酯键的酶活性成份。该酶具有最适pH8.8—9.1,在60℃(反应30分钟)条件下具有最大活性。Km=1.72×10^(-4)mol/L,Na_3PO_4、EDTA和半胱氨酸可抑制其活性,而CuSO_4、腺苷、胸苷、NaN_3、E600、PCMB、DFP和毒扁豆碱等对其活性没有影响。Mg^(++)可激活酶活性,并能解除EDTA的抑制作用。 此酶不能水解5′-NPDase和APase的底物,有关性质也与5′-NPDase和APasc有区别。本文将此酶暂定名为“膦酸单酯酶”。
Enzyme capable of hydrolyzing the 4-methylumbelliferyl phenylphos-phonate to 4-methylumbellif erone and phenylphosphonic acid has been detected in human serum. It has Km at 1.72 × 10-4mol/L., with optimum pH of 8.8-9.1 and maxium activity at 60℃(30 min). The enzymic activity can be inhibited by Na3PO4 EDTA and Cysteine but activited by Mg2+. No effect of CuSO4、 NaN3、E600、PCMB、DFP and Eserine on the enzymic activity was found. It can not hydrolyze substrates for 5'-nucleotide phosphodiesterase and alkaline phosphatase. The enzyme was considered as 'Phosphonate monoesterase'
关键词
人血清
膦酸单酯酶
Phosphonate monoesterase
Phosphodiesterase I
5' -Nucleotide phos-phodiesterase
Alkaline phosphatase
