【摘要】 背景与目的:血浆中含有氨基脲敏感型胺氧化酶(SSAO)。本文研究以甲胺为底物的兔血浆中具有SSAO酶活性的蛋白组分的酶动力学参数。材料与方法:利用弱阴离子交换柱层析分离兔血浆蛋白,测定各收集组分的SSAO酶活性;以甲胺为底物测定SSAO酶动力学参数。结果:从兔血浆蛋白中分离得到两个具有SSAO酶活性的蛋白组分A和B。以甲胺为底物,未处理的血浆SSAO的酶动力学参数Km=(1.83±0.13)mmol/L,Vmax=(0.12±0.003)nmol/(min·mg)。蛋白组分B的酶动力学参数Km值(2.05±0.43)mmol/L小于蛋白组分A的Km值(3.14±0.63)mmol/L。组分B的酶动力学参数Vmax值(1.46±0.10)nmol/(min·mg)小于组分A的Vmax值(2.85±0.20)nmol/(min·mg)。结论:兔血浆含有两种SSAO酶,均可以催化甲胺氧化脱氨生成甲醛;组分A、B动力学特征有所不同。更多还原

【Abstract】 BACKGROUND AND AIM: To purify and investigate the enzyme kinetic properties of rabbit plasma semicarbazide-sensitive amine oxidases(SSAO),using methylamine as substrate.MATERIALS AND METHODS: Formaldehyde,an oxidative deamination product of methylamine,was analyzed by HPLC.Rabbit plasma SSAO was purified by chromatography with DEAE-sepharose FF(eluted with 30 mmol/L and then 100 mmol/L sodium phosphate buffers,all at pH 7.0),then assayed and Michaelis-Menten analyzed.RESULTS: Two fractions of plasma(labeled as peak A and peak B) obtained were catalytically active with methylamine as substrate.The kinetic parameters Km and Vmax of plasma were(1.83±0.13) mmol/L and(0.12±0.003)nmol/(min·mg),respectively.The Km of peak B(2.05±0.43)mmol/L was lower than that of peak A(3.14±0.63)mmol/L,the Vmax of the peak B(1.46±0.10) nmol/(min·mg) was lower than that of peak A(2.85±0.20) nmol/(min·mg).CONCLUSION: In rabbit plasma,there were two kinds of SSAO,which could catalyze the oxidative deamination of methylamine into formaldehyde,had significantly different kinetic parameters.更多还原