泥蚶血液中δ-氨基乙酰丙酸脱水酶的测定

ASSAY OF δ AMINOLAEVULINIC ACID DEHYDRATASE IN BLOOD OF ARCA GRANOSA LINNUS

铅对哺乳动物血液中的卟胆元合成酶δ-氨基乙酰丙酸脱水酶(δ-ALAD)有明显的抑制效应,已得到广泛证实。某些海洋鱼类的致毒实验表明:铅对鱼血中δ-ALAD的毒性效应会破坏鱼的造血功能。由于δ-ALAD对铅的反应灵敏且专一,所以血中δ-ALAD酶的活性已成为检验铅中毒和评价生态环境铅污染潜在危害的指标。然而有关海洋双壳类动物血中δ-ALAD的铅致毒效应研究未见过报道,这与缺乏可直接应用的酶测方法有关。为开展这方面研究,我们对测定血液δ-ALAD酶活性的经典方法进行了改进,并应用于泥蚶(Arca granosa Linnus)血液δ-ALAD的测定。实验提出一种简便的血样处理方法,并选择最适酶促反应条件,从而建立泥蚶血液δ-ALAD酶活性测定方法。

A method for the determination ofδ-aminolaevulinic acid dehydratase(δ-ALAD)activity in blood of A.granosa is reported.Blood samples were prepared by centrifugation-hemotolysis.The optimal reaction conditions are:in Na2HPO4-NaH2PO4 buffer solution pH=7.0,40℃incubation temperature,60 min.for duration and 0.005M for substract concentration.The results showed that theδ-ALAD activity in blood of A.granosa was 161±41 units(n mol PBG/hr.ml RBC)and there was a significant negative correlation betweenδ-ALAD activity and lead concentration in blood expoure to lead(Pb2+)in seawater.It provides a sensitive and easy enzymic assay method for studying lead toxicical effect on A.granola.