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【医学ppt课件】 第六章 酶(enzyme)

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医学ppt课件 【医学ppt课件】 enzyme 酶ppt课件
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Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. 第六章 酶(enzyme) . 第一节 酶是生物催化剂 § 1926年,Sumner从刀豆 § 中分离出脲酶结晶,后来 § Northrop得到了胃蛋白酶、 § 胰和胰凝乳的结晶。 § 一 酶的生物学意义 § 生物体内一切化学反应,几 § 乎都是在酶催化下进行的,只要有生命的地方,就 有酶在起作用,生命不能离开酶而存在。 § 酶是生物体内一类具有催化活性和特定空间构相的 生物大分子,包括蛋白质和核酸。 Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. § 二 酶作用的专一性 § 1.立体化学专一性 § (1)旋光异构专一性 (2)几何异构专一性 Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. § 2.非立体化学专一性 § (1)键专一性 A B (2)基团专一性 § (3)绝对专一性 § Fisher 锁钥学说 § Koshland § 诱导契合学说 Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. 三 酶的分类与命名 § (一) 酶的分类 国际酶学委员会(IEC)分六类 § 1.氧化还原酶类(oxidoreductases):催化氧化还原反应 § 2.转移酶类(transferases):催化功能基团的转移 § 3.水解酶类(hydrolases):催化水 解反应 4.裂合酶类(lyases):催化水,氨或co2 的去除或加入 § 5.异构酶类(isomerases):催化各种类型的异构作用 § 6.合成酶类(ligases):催化消耗ATP的成键反应 § ( 二 ) 酶的命名 § 1. 习惯命名法:如反应类型蛋白水解酶、乳酸脱氢酶等 ; 底物名称:如蔗糖酶、胆碱酯酶、蛋白酶等。 § 底物加来源名称:如胃蛋白酶、唾液淀粉酶等。 § 2 .系统命名法 E.C2.7.1.1. ATP:葡萄糖磷酸转移酶 Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. . . Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. 第二节 酶的结构与功能 § 一 酶的化学组成 § 酶和其他蛋白质一样,分简单蛋白质单纯酶和结合蛋白 质结合酶两类。结合酶(conjugated enzyme)酶蛋白 (apoenzyme)辅助因子(cofactor)辅(coenzyme, Co)辅基(prosthetic group)全酶(holoenzyme) § 全酶 = 酶蛋白 + 辅助因子 (辅酶或辅基) § 1 单体酶 只有一条多肽链分子量约 13000—35000 § 2 寡聚酶 由几条到几十条亚基组 成 35000到几百万 § 3 多酶体系 由几种酶彼此嵌合的复合体,几百万以上 § 二 酶的辅助因子 (辅酶或辅基) § 1.无机离子对酶的作用 § 2.维生素与辅酶的关系 3.蛋白质类辅酶 Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. . Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. 血红素(heme group) 硫氧还原蛋白(thioredoxins) § 三、酶的结构与功能 (一)酶的活性中心和必需基团 Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. (二)酶的活性中心与酶作用的专一性 § (三)空间结构与催化活性 Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. . § (四)酶原的激活 § 第三节 酶的作用机制 § 一.酶能显著降低 § 反应活化能 Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. 二 中间复合物学说和酶作用的过度态 § 酶 (E) 底物 (S) 酶底物复合物 (ES) 产物 (P) § E + S ≒ ES ——→ E + P 三 酶作用高效率的机制 § (一)底物的 “趋近” 和 “定向” 效应 § 趋近效应(approximation) § 定向效应(oreintation) Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. § (二)底物变形与张力作用 Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. § (三) 共价催化作用 1.亲核催化作用 § 非催化反应 RX +H2O --慢 ROH + HX § 酶催化反应 RX + E-OH –快ROE + HX § ROE+ H2O –快 ROH + E-OH § 总反应 RX + H2O -酶(快)  ROH + HX § 2. .亲电子催化作用: 如—NH3 § (四)酸碱催化作用 § 四 核糖酶与抗体酶的催化反应 § (一)核酶(ribozyme) Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. § ( 二 ) 抗体酶(abzyme) Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. § (1) 酰基转移反应: § (2) 水解反应: Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. 第四节 酶促反应的动力学 § 一.底物浓度对酶反应速度的影响 § Henri “酶底物中间复合体学说” § S + E ≒ ES -- E + P Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. (一)米氏方程及其推导 Michaelis 和Menten . Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. § 米氏方程: § V = K3 [ES] (5-2)ES生成速度= K1 [E][S](5-3) § ES解离速度 =(K2+K3) [ES] ( 5-4) ( 5-5)重排: § [ES]= [E][S]/Km (5-7) 恒态时 [E]= [Eo]- [ES]( 5-8) Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. 将( 5-8)代入 (5-7)式,得到: [ES]=( [Eo]- [ES]) [S]/Km (5-9) § 从(5-9)式中求解[ES] § 或 [ES]= [Eo] [S]/Km +[S](5-11) § 将(5-11)代入 (5-2),得: § V=K3 [Eo] [S]/Km +[S](5-12) 故V =Vmax Vmax= K3 [Eo] [Eo]= Vmax / K3 (5-13) 将(5-13代入5-12) V= Vmax [S]/Km +[S](5-14) Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. (5-14)式就是米氏方程, 整理得: VKm+V [S]= Vmax [S] (5-15) VKm +V [S]- Vmax [S]- VmaxKm = - VmaxKm( 5-16) (V-Vmax)( [S]+Km)= - VmaxKm(5-17) (5-17)可写成(x-a)(y+b)=K (二)米氏常数的意义 酶促反应处于V=1/2Vmax时,则米氏方程为: Vmax/2= Vmax [S]/ Km +[S]. Km+ [S]=2 [S]. Km= [S] (1)1/Km愈大,酶促反应易于进行。 (2) [S]=3Km时代入(5-14)式 V= Vmax.3Km/ Km +3Km=3/4Vmax=75%Vmax Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. (3)在测定酶活性时[S]值大于Km10倍以上;… (三米氏常数的求法 1. Lineweaver Burk 方程 米氏方程 两边取倒数 2.Hanes作图法: (5-17)两侧均乘以[S]可得: [S]/V=1/Vmax [S]+ Km/ Vmax (5-19) Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. 二. pH的影响与最适pH § 1.影响酶和底物的解离; § 2. .影响酶分子的构象。 § 三 温度的影响与 § 最适温度 Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. §四 酶浓度的影响 §V=Vmax[S]/Km+[S] §因为Vmax=K3 [Eo] 所以V=K3 [Eo] [S]/ Km +[S] 为一直线,这是酶活力测定的依据。 五 激活剂的影响 六 抑制剂的影响 Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. § (一)不可逆抑制 1.非专一性不可逆抑制 : § 2.专一性不可逆抑制 : Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. § (二) 可逆抑制 1.竟争性抑制(competitive inhibition) Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. § Ks=[E][S]/[ES], 故[ES]= [E][S]/ Ks (5-21) § Ki=[E][I]/[EI], 故[EI]= [E][I]/ Ks (5-22) § 即 V=Ko[ES] Vmax= Ko[Eo] (5-23) § 故 V/ Vmax= [ES]/ [Eo] (5-24) § 而酶的总浓度[Eo]=[E]+ [ES]+ [EI] (5-25) § 将(5-25)式代入(5-24)式,再将(5-21) (5-22)式中 的[ES] [EI]值代入(5-25)式 Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. . Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. (5-28) 和(5-29式是竟争性抑制作用的反应速度公式 竟争性抑制作用的例子: Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. § 竟争性抑制作用的例子:磺氨类药物 § 非竟争性抑制: Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. § 非竟争性抑制: Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. § 根据平衡学说: § [ES]= [E][S]/Ks [IE]=[E] [I]/Ki (5-30) § [IES]=[ES] [I]/Ki.= [E][S] [I]/ KsKi. (5-31) 或[IES]= [IE][S]/Ks.= [E][S] [I]/ KiKs. (5-32) § 而[Eo]= [E]+[ES]+ [IE] + [IES] (5-33) Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. § 非竟争性抑制动力学图: § 反竟争性抑制作用: Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. § 反竟争性抑制作用: Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. § [ES] = [E] [S] /Ks (5-36) § [IES]=[ES] [I]/Ki= [E][S] [I]/ Ks Ki (5-37) § [Eo]= [E]+[ES]+ [IE] + [IES] (5-38) Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. § 反竟争性抑制动力学图: Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. § (三)过渡态类似物与自杀底物 Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. § 自杀底物Ss自杀底物在酶催化下产生的抑制剂Is § 第五节 酶的分离、提纯及活性测定 § 一 酶的分离、提纯 § (一 ) 酶的抽提 § (二 )酶的纯化 Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. § 酶的纯度用比活力表示,比活力即每毫克蛋白(或每 § 毫克蛋白氮)所含的酶活力单位数。 § 比活力(纯度)= 活力单位数/毫克蛋白(氮) Through this publicity campaign, further improve the sense of business integrity of tourism enterprises to help tourism consumers and operators to safeguard the legitimate rights and interests, to ensure that our City's tourism sustainable, healthy and coordinated Development. . § 二 酶的活力测定 酶的活力高低以酶活力单位(U)表示。1961年国际 酶学会议规定:1个酶
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