欢迎来到天天文库
浏览记录
ID:55679353
大小:362.54 KB
页数:5页
时间:2020-05-24
《木犀草素对酪氨酸酶活性抑制及构象诱导作用.pdf》由会员上传分享,免费在线阅读,更多相关内容在应用文档-天天文库。
1、现代食品科技ModernFoodScienceandTechnology2014,Vo1.30,No.7木犀草素对酪氨酸酶活性抑制及构象诱导作用刘华’,李仕祥,钟业俊。,吴丹(1.江西科技师范大学生命科学学院,江西南昌330047)(2.江西省食品药品监督管理局,江西南昌330029)(3.南昌大学食品科学与技术国家重点实验室,江西南昌330013)摘要:在37℃、pH6.8的磷酸盐(100mmol/L)缓冲体系中,采用酶抑制动力学方法,研究了木犀草素对酪氨酸酶的抑制作用、抑制类型和抑制动力学常数,并探讨了木犀草素对酪氨酸酶表面疏
2、水性和二级结构的影响。结果表明,木犀草素是一种可逆的非竞争型酪氨酸酶抑制剂(半抑制率Ic50为55.35+1.51~tg/m,抑制常数为63.57-4-2.12~tg/mL);失活动力学时间进程分析表明木犀草素能快速与酪氨酸酶发生作用并迅速降低酶的活性;荧光光谱分析显示木犀草素能显著增强酪氨酸酶的表面疏水性;圆二色谱分析表明木犀草素诱导酪氨酸酶的构象伸展和解折叠,随着木犀草素浓度的增加,螺旋含量由31I3%逐渐增加到41.6%,由此可见木犀草素能够诱导酪氨酸酶的构象发生部分改变,使酶结构变化而不利于其形成活性中心,进而降低酪氨酸酶
3、的活力。关键词:木犀草素;酪氨酸酶;抑制作用;表面疏抽}生;二级结构文章篇号:1673.9078(2014)7.51.55Effect0fLuteolinonActivi~andConformation0fTyrosinase.—一LIUHua,LIShi-xiang,ZHONGYe-jun,wUDan(1.SchoolofLi~Science,JiangxiScience&TechnologyNormalUniversity,Nanchang330047,China)(2.TheFoodandDrugAdministration
4、ofJiangxiProvince,Nanchang330029,China)(3.TheN~ionalKeyLaboratoryofFoodScience,NanchangUniversity,Nanchang330013,China)Abstract:Theefectsofluteolinoninhibitoryaction,inhibitorytypeandinhibitorykineticsoftyrosinasewereinvestigatedusingthemethodofenzymeinhibitionkinetic
5、sin37℃,pH6.8sodiumphosphatebufer(100retool/L)system,thechangesofsurfacehydrophobicityandsecondalystructureoftyrosinasewerealsoprobed.Theresultsshowedthatluteolinwasareversibleandnoncompetitiveinhibitor(thehalfinhibitionconcentration(IC50)andinhibitionconstant(Ki)wereo
6、btainedtobe55.35~g/mLand63.57~tg/mL,respectively).Thetime—coursesanalysisofinactivationkineticsindicatedthatluteolininteractedwithtyrosinasequicEyandinhibitedtheacticityofenzymempi~y.Fluorescencespectrumanalysisshowedthatluteolinsignificantlyincreasedthesurfacehydroph
7、obicityoftyrosinase.Circulardichroismspectraanalysisshowedthebindingofluteolintotyrosinaseinducedtheunfoldingofconformationandthegradualincreaseof0【一helixcontentoftyrosinase(from31.3%to41.6%1.Theresultsofspectraanalysisindicatedthatthebindingofluteolintotyrosinasealte
8、redtheconformationoftyrosinasewhichwasnotconducivetotheformationofactivecenter,therebyreducingtheactivityoftyrosinase.Keywor
此文档下载收益归作者所有