生物化學(xué)第二章酶

1、會計學(xué)1生物化學(xué)第二章酶生物化學(xué)第二章酶酶單成份酶：脲酶、蛋白酶、淀粉酶、核糖核酸酶等。雙成份酶酶蛋白輔因子（簡單蛋白質(zhì)）（結(jié)合蛋白質(zhì)）（apoenzyme）（cofacter)輔酶（coenzyme)輔基(prosthetic group)全酶(holoenzyme）= 酶蛋白 + 輔因子CH2OHCH2OHA1A2麥角固醇7-脫氫膽固醇22-雙氫麥角固醇7-脫氫谷固醇維生素D2維生素D3維生素D4維生素D5HOROHOR2R1R3OOOOCH2CHC(CH3)CH2CH25CHC(CH3)2Cl-N+SCH3CH2CH2OHNNNH2H3CCH2NNNH2H3CCH2N+SCH3CH2CH

2、2OPOOPOHOHOOHCl-NCCNHNNOOCH2CHCHCHCH2OPOHOHOHOHOOHCH3CH3CH3CH3NCCNHNNOOCH2CHCHCHCH2OPOOHOHOHOOHOCH2OHOHNNNH2NNFMN FADCH2CCH3CH3CHOHCONHCH2CH2COHCOOHOCH2CCH3CH3CHOHCONHCH2CH2CNHCH2CH2SHOOOOHPOOHHONNNH2NNOPOOOHPOOOHCH2NCOOHNCONH2OCH2OPOPOCH2OHOHO OO-O-N+CONH2OOHOH(OPO3H2)NNNH2NNNH3CHOCH2NH2CH2OHNH3CHO

3、CHOCH2OHNH3CHOCHOCH2OPOHOOHNH3CHOCH2NH2CH2OPOHOOH磷酸吡哆醛 磷酸吡哆胺HNNHCOCHH2CS(CH2)4COOHNNH2NOHNNHHCH2HHHNHCONHCHCOOHCH2CH2COOHCCCCCCH2OHOHOHOHHOHOOCCOOOHHOHCH2OHCCCSCHSCHCH2CH2CH2CH2CH2COOHOOCH3OCH3OCH3(CH2CH CCH2)nHCH3n=6-10催化部位(Catalytic site): 酶分子中促使底物發(fā)生化學(xué)變化的部位稱為催化部位。l通常將酶的結(jié)合部位和催化部位總稱為酶的活性部位或活性中心。l結(jié)合部

4、位決定酶的專一性，l催化部位決定酶所催化反應(yīng)的性質(zhì)。 調(diào)控部位(Regulatory site):酶分子中存在著一些可以與其他分子發(fā)生某種程度的結(jié)合的部位，從而引起酶分子空間構(gòu)象的變化，對酶起激活或抑制作用H2NCHCCH2OHOOHOHH2NCHCCH2OHOSHSHH2NCHCCH2OHONNHNNHH2NCHCCH2OHOCH2COHOH2NCHCCH2OHOCOHOCOOHH2NCHCCH2OHOCH2CH2CH2NH2NH2H2NCHCCH2OHOOHOHCH3CHCOOHOHNAD+H+CH3CCOOHONADHCH3CHCOOHNH2HOOCCH2CH2CCOOHOHOOCCH2

5、CH2CHCOOHNH2CH3CCOOHOH2OCOOCH2CH3RRCOOHCH3CH2OHHOOCCH=CHCOOHH2OHOOCCH2CHCOOHOHOCH2OHOHOHOHOHOCH2OHCH2OHOHOHOH33333333335555555555BBBBBPPP+POHPPBBBBPPPPPBP-COOH, -NH3, -SH,+OHNHNH+-COO , -NH2, -S , -.-O-NHN:V=Vmax SKm + SK Km m 米氏常數(shù)米氏常數(shù)V Vmax max 最大反應(yīng)速度最大反應(yīng)速度 1 1 K Km 1 1m 1 1 = = + + V V V Vmax S max S V Vmaxmax-4-202468100.00.20.40.60.81.01/S(1/mmol.L-1)1/v1/Vmax斜率斜率=Km/Vmax-1/Km102030405060708090020406080100Temperature OCRelative Activity (%)最適溫度 動力學(xué)特點(diǎn)：不符合米曼方程雙曲線。V=Vmax SKm + SNH3CHOCH2NH2CH2O