生物氧化 浙江大学生物化学及实验(丙)课件

Interlocking gears (coupHng device)
Battery (two leal species of
different reduction
potential)
Motor (energy transducer)
(a)
Weight being lifted (mechanical work)
膜结构。外膜outer membrane可允许小分子 (Mr<5000)和离子自 由通过。内膜inner membrane只允许
在内膜上有特异通道的物质通过，对大部分的小分子及离 子不通透。
外膜
Outer membrane ---- Inner membrane
内膜
-Cristae -Matrix
基质
CH2
产—8。一
CO2
CH2
c—COOJ
o
II
a-Ketoglutarate
C—S-CoA
II
o
Succinyl-CoA
CoA-SH
CO2
④
Oxidative
decarboxylation
二、电子传递链：又称为呼吸链。是由存在于线粒体内膜上 的一系列能接受氢或电子的中间传递体组成。
•电子传递链的组成成分
Dehydrogenation
CH2—coo一
CH2
coo-
Succinate CoA-SH
succinyl-CoA synthetase
GTP (ATP)
⑥
Substrate-level phosphorylation
GDP (ADP)
+R
\a-ketoglutarate dehydrogenase \ complex CH2—COO~
•电子传递过程：电子从NADH/FADH2到。2的过程。 ♦复合物I： NADH-CoQ氧化还原酶，又称泛醍氧化还原 酶。是一
个由42条多肽链组成的大的酶复合物。其中包含 FMN黄素蛋白和 至少6个铁硫中心。
膜内空间
IVIatriic， (z
》基质 side
电子走向：NADHTFMNTFC-STCOQ 每传递
CH2—COOHO—C—COCT
CH2—COO~ Citrate
malate
aconitase
Dehydration H2O
COO-
Malate
HO—CH CH2 COO-
⑦ Hydration
fumarase
H2O Fumarate
COOCH II HC
COO-
FADH2
succinate dehydrogenase
在形式，氧化 型、半醍型和还原型。
H3CO
Coenzyme QH • or ubise miquinone (radical or semiquinone form)
IH-)
Coenzyme QH2 or ubiquinol (reduced or hydroquinone form)
♦细胞色素C：是一类含铁卟啉（血红素）辅基的蛋白质。根 据其吸收光谱的不同，可分为a,b,c三类。
c2 +o o/ S c O %c - o A IH3 Accetyl-CoA
= -33.4 keJ/mol
⑥
Dehydrogenation
①
Condensation
Acetyl-CoA
o
II
—CC—HS3-CoA
H2O
CoA-SH
o=c—cocr
CH2—COO-
Oxaloacetate
citrate synthase
+ Pi
Mitochondrion (electrochemical
transducer)
Muscle contraction (mechanical work)
葡萄糖 + 2 ADP + 2Pi+ 2NAD+一 2 丙酮酸 + 2ATP + 2H2O +(2NADH)+ 2H+
\ co —/ c — Pycruvate
cytochromes, has a long isoprenoid tail attached to one of the
血红素
CHO 'CH2CH2COO Heme A
(in a-type cytochromes)
five-membered rings. The conjugated double-bond 珅 stem (shaded pink) of the porphyrin ring accounts for the absoeption of visible light by these hemes.
步释放的。
•生物氧化的所产生的能量首先转移到一些高能化合物中。
•生物氧化的三个阶段
Amino acids
FatXy acids
dxacose
电子传递和氧化磷酸化
JVDP -+- P. ATP
乙酰CoA的氧化
Stage 3 Electron t.ransfei-smd oxidative
•生物氧化的场所：线粒体是真核生物生物氧化的场所。线 粒体有两层
Outer membrane. Because it contains a large channel-forming protein (called porin), the outer membrane is permeable to all molecules of 5000 daltons or less.
Intermembrane space. This space contains several enzymes that use the ATP passing out of the matrix to phosphorylate other nucleotides.
^wes (chain of electron carriers)
♦烟酰胺腺嘌吟核苷酸NAD+ :是许多脱氢酶的辅酶。
two high-energy electrons from sugar oxidation
unstable isomer
H HH
O H
* C
CC
H
HX
C
CH
ELECTRON DONATION
A
NADH
hydride ion H：
BOND REARRANGEMENT
代谢物 已氧化代谢物
FMN/FAD
FMNH2/FADH2
FMN II -»( nt* <1 u cc<l or hy<1 roq u i n o n c form )
♦铁硫蛋白：是指蛋白中Fe原子与无机S和/或蛋白质Cys残基 的s原子 相连形成Fe-S中心。最简单的Fe-S中心是单个Fe与4 个Cys的-SH相
Inner membrane. Folded into numerous cristae, the inner membrane contains proteins that carry out the oxidation reactions of the electron-transport chain and the ATP synthase that makes ATP in the matrix.
Fatty acyl—CoA
C FAD嵐
!<ADH
Fe-S
Complex
II
y
Complex I
Complex III
2 H・♦ V2 02
Cyt c —► a Cyt —► Cyt
a3
Complex IV
Electron transport
♦复合物小：CoQ-细胞色素C氧化还原酶
CHa
coordinated with a central Fe ion, either Fe2 * or Fe”. Iron protoporphyrin IX is found in b-type cytochromes and in
CHa
CH2CH2COO_
hemoglobin and myoglobin (see Fig. 4-16). Heme c is covalently bound to the protein of cytochrome c through thioether bonds to two Cys residues. Heme a, found in a-type
Rough endoplasmic reticulum
(b)
基质：指位于线粒体内膜包围空间内的液体。里面含有大量的酶，如 丙酮酸氧
化、脂肪酸氧化、柠檬酸循环和氨基酸氧化所需的酶。
内膜：向内折叠为多个嶠。内膜上镶嵌有电子传递链相关蛋白和ATP 合成
酶。
膜内空间：为线粒体内膜和外膜之间的空间。
Matrix. This space contains a highly concentrated mixture of hundreds of enzymes, including those required for the oxidation of pyruvate and fatty acids and for the citric acid cycle.
CH?—CH
、 CH；
CH=CH.,
N
CHI
N—Fe—N
Cys—S CHyCH
S—Cys CHCH
CH：1
__
CH2CH2COO
CII2CIl2COO-
血红素
CH3 CH2CH2COO Iron protoporphyrin IX