Coenzymes(psuedoscince naming)

这是一篇关于Coenzymes(psuedoscince naming)的思维导图，主要内容有coreactant phospate carriers、coreactant hydride ion e- carriers、prosthetic e- transfer groups、defination等。

Coenzymes(psuedoscince naming)

• coreactant phospate carriers
  • Adanine+Guanosine
    • ATP,ADP,AMP
    • GTP,GDP,GMP
  • reactions catalysts
    • phosphorylation
      • many kinases
      • often very spontaneous, ATP has very high energy structure.
        • columbic repulsive forces between neighboring negative charged phosphates
    • it self undergoes
      • hydrolysis
      • resupplemented by oxidative phosphorylation/photophosphorylation
• coreactant hydride ion e- carriers
  • Nicotinamide adenine dinucleotides
    • oxidated state
      • NAD+
      • NADP+
        • final electrons acceptor in photophosphorylation
    • reducted state
      • NADH
        • electron donator in oxidative phosphorylation
      • NADPH
        • supplies electrons for anabolic reactions
    • access enzyme class
      • Nicotinamide nucleotide-linked dehydrogenase
        • reversible reactions
      • binding
        • loose, noncovalent
        • should be considered as reactant
      • reduction potential
        • independent of enzymes
  • reaction catalysts
    • Oxidation
      • accepts a hydride ion H:-
    • Reduction
      • donates a hydride ion H:-
      • Strong reducing potential
• prosthetic e- transfer groups
  • direct e- carriers
    • as in reduction of Fe3+---Fe2+
    • cytochromes(proteins)
      • a-type cytochromes
        • Heme A(prosthetic group)
        • noncovalent interaction
      • b-type cytochromes
        • Iron protoporphyrin IX
        • noncovalent interaction
      • c-type cytochromes
        • Heme C
        • covalent attachment
      • distinguish
        • light absorbtion spectra
          • a~600nm
          • b~560nm
          • c~550nm
        • most integral membrane proteins
          • exept cytochrome c: periphral protein through electrostatic interaction
    • Ion-sulfur centers
      • 1 Fe sulfur center
      • 2 Fe 2S sulfur center
      • 4 Fe 4S sufur center
      • Rieske iron-sulfur protein
      • S in cys residues
        • all requires 4 sulfur in cys residues for stabalization
          • exept the rieske one stabalized by His
  • hydride ion 2 e- carriers
  • hydrogen atom 1 e- carriers
    • hydrophobic quinone
      • coenzyme Q
        • Ubiquinone(Q)
          • fully oxidized
        • Semiquinone radical(.QH)
        • Ubiquinol(QH2）
          • fully reduced
      • chloroquinone
      • plastoquinone
      • lipid soloble
        • move freely in hydrophobic membrane region
    • Flavin nucleotides
      • FADH2
        • electrons donator in respiratory ETC
      • FADH
      • FAD+
      • access proteins
        • Flavoproteins
        • binding
          • tight bonding, sometimes covalent
          • should be considered as part of active site (prosthetic group)
        • reduction potential
          • protein dependent
      • e- transfer
        • can transfer either 1 or 2 e-
• defination
  • prosthetic group
    • A metal ion or an organic compound (other than amino acids) that is covalently bound to a protein and is essential to its activity
    • it's reduction potential dependent on microenviroment of binded proteins
  • reduction potential
    • the reaction goes into direction of increasing reduction potential
  • reducing equivalent
    • a single electron equivalent transferred in an oxidation-reduction reaction
• e- transfer
  • remove two hydrogen atoms on substrate
  • release one as proton and itself accept a hydride ion H:-
  • seperate pools in cell for NADPH and NADH with different redox potentials
    • [reduced form]/[oxidized form]
      • relative high for NADPH
        • more reduced form to catalyst anabolic reductions
      • relative low for NADH
        • more oxidized form to catalyst the metabolism oxidation