摘要
目的探讨葎草酮对人胃癌SGC-7901细胞N-乙酰基转移酶1(NAT1)酶动力学常数的影响。方法采用HPLC法,以NAT1酶特异性底物对氨基苯甲酸(PABA)为底物,以SGC-7901完整细胞及细胞质内PABA被NAT1乙酰化为Ac-PABA的速度为NAT1酶的反应速率,采用双倒数作图法,以底物PABA浓度的倒数对NAT1反应速率的倒数进行直线回归,得出回归方程,计算米氏常数(Km)和最大反应速率(Vmax)。结果酶动力学研究表明,以PABA为底物,对于SGC-7901完整细胞,阴性对照组的Km和Vmax分别为(3.910±0.087)μmol/L、(0.306 0±0.006 7)pmol(1×106个细胞),葎草酮组的Km和Vmax分别为(3.830±0.123)μmol/L、(0.275 0±0.005 8)pmol(1×106个细胞),对于SGC-7901细胞质,阴性对照组的Km和Vmax分别为(760.2±210.2)μmol/L、(0.191 0±0.043 7)pmol/(mg.min),葎草酮组的Km和Vmax分别为(449.0±72.9)μmol/L和(0.094 0±0.010 4)pmol/(mg.min),数据经统计学处理表明对SGC-7901完整细胞或细胞质中的NAT1酶,阴性对照组和葎草酮组的Km没有统计学差异,而Vmax有显著差异。结论葎草酮是SGC-7901人胃癌细胞NAT1酶PABA底物的非竞争性抑制剂。
Objective To explore the effects of humulon on kinetic parameters of N-acetyltransferase-1（NAT1） of human gastric cancer SGC-7901.Methods Employing HPLC,using para-aminobenzoic acid（PABA） as substrate,in intact SGC-7901 cells and their cytoplasm,taking the speed of PABA being acetylated to Ac-PABA by NAT1 as the rate of NAT1,using double reciprocal plot,taking the reciprocal of concentration of PABA and reaction rate of NAT1 as coordinates,regression equation was obtainied and the Michaelis constant（Km） and maximum reaction velocity（Vmax） were calculated.Results Study on enzyme kinetics demonstrated,as for intact SGC-7901 cells,Km and Vmax of control group were（3.910±0.087） μmol/L and（0.306 0±0.006 7） pmol/L（1×106 cells）,respectively,Km and Vmax of the humulon group were（3.830±0.123） μmol/L and（0.275 0±0.005 8） pmol（1×106 cells）,respectively.As for the cytoplasm of SGC-7901 cells,Km and Vmax of control group were（760.2±210.2） μmol/L and（0.191 0±0.043 7） pmol/（mg·min）,Km and Vmax of the humulon group were（449.0±72.9） μmol/L and（0.094 0±0.010 4） pmol/（mg·min）.Statistically,as for intact SGC-7901 cells or their cytoplasm,there was no difference of the Km between control group and humulon group,but there was remarkable difference of Vmax between control group and humulon group,P0.01 for intact cell and P0.05 for cytoplasm.Conclusion Humulon is a noncompetitive inhibitor of NAT1 in SGC-7901 cells.
出处
《中草药》
CAS
CSCD
北大核心
2010年第6期931-934,共4页
Chinese Traditional and Herbal Drugs
基金
黑龙江省教育厅重点项目(11511102)
