Chapter 19 Oxidative phosphorylation and photophosphorylation (氧化磷酸化和光合磷酸化) Generation of atp by using a across membrane proton gradient, which is generated from electron flowing through a chain of carriers
Chapter 19 Oxidative phosphorylation and photophosphorylation （氧化磷酸化和光合磷酸化） Generation of ATP by using a acrossmembrane proton gradient, which is generated from electron flowing through a chain of carriers
ATP is synthesized using the same strategy in oxidative phosphorylation and photophosphorylation Oxidative phosphorylation is the process in which ATP is generated as a result of electron flow from Nadh or FADH, to O, via a series of membrane-bound electron carriers, called the respiratory chain(reducing O2 to H2O at the end) Photophosphorylation is the process in which ATP(and NADPH) is synthesized as a result of electron flow from HO to adpt via a series of membrane-bound electron carriers(oxidizing h2o to O2 at the beginning
1. ATP is synthesized using the same strategy in oxidative phosphorylation and photophosphorylation • Oxidative phosphorylation is the process in which ATP is generated as a result of electron flow from NADH or FADH2 to O2 via a series of membrane-bound electron carriers, called the respiratory chain (reducing O2 to H2O at the end). • Photophosphorylation is the process in which ATP (and NADPH) is synthesized as a result of electron flow from H2O to NADP+ via a series of membrane-bound electron carriers (oxidizing H2O to O2 at the beginning)
Oxidative phosphorylation and photophosphorylation are mechanistically similar Both involve the flow of electrons through a chain of membrane bound carriers The energy released from"downhill electron flow is first used for uphill" pumping of protons to produce a proton gradient(thus a transmembrane electrochemical potential) across a biomembrane aTP is then synthesized by a downhill transmembrane flow of protons through a specific protein machinery (ATP synthase)
• Oxidative phosphorylation and photophosphorylation are mechanistically similar: – Both involve the flow of electrons through a chain of membranebound carriers. – The energy released from “downhill” electron flow is first used for “uphill” pumping of protons to produce a proton gradient （thus a transmembrane electrochemical potential) across a biomembrane. – ATP is then synthesized by a “downhill” transmembrane flow of protons through a specific protein machinery (ATP synthase)
Intermembrane nner Transporter Citric acid cycle SCoA Co, o P+GDP GTP Pyruvate CH,-C-SCoA Acetyl CoA 3NAD 3NADH FAD FADH HSCo. ATP+ Anrt HSCOA →→FADH HSCOA NAD"NADH-FADMitochondrial Transporter matrix NADH NAD P 2e+H"+ao2→H2O NADH NAD. FAD Oxidative NAD Phosphorylation On inner menbrane of mitochondria) Electron transport complexes Transport of metabolites Pyruvate dehydrogenase and citric acid cycle into the mitochondrion ATP synthesis by FoF Fatty acid metabolism using proton-motive force Electron transport fror ATP export, ADP and P, import NADH and FADH, to oxygen; generation of proton-motive force
Oxidative Phosphorylation (0n inner membrane of mitochondria)
Photophosphorylation (on thylakoid of chloroplasts) Light Light 2H' NADP+H NADPH Stroma PSI tFd bo PSI complex Mn Plasto- cyanin 2H,.O2+ 4H 2H+ Lumen Thylakoid F membrane ADP + P ATP
Photophosphorylation (on thylakoid of chloroplasts)