HOMEPRODUCTSCOMPANYCONTACTFAQResearchDictionaryPharmaSign Up FREE or Login

Direct evidence of active-site reduction and photodriven catalysis in sensitized hydrogenase assemblies.

Abstract
We report photocatalytic H(2) production by hydrogenase (H(2)ase)-quantum dot (QD) hybrid assemblies. Quenching of the CdTe exciton emission was observed, consistent with electron transfer from the quantum dot to H(2)ase. GC analysis showed light-driven H(2) production in the presence of a sacrificial electron donor with an efficiency of 4%, which is likely a lower limit for these hybrid systems. FTIR spectroscopy was employed for direct observation of active-site reduction in unprecedented detail for photodriven H(2)ase catalysis with sensitivity toward both H(2)ase and the sacrificial electron donor. Photosensitization with Ru(bpy)(3)(2+) showed distinct FTIR photoreduction properties, generating all of the states along the steady-state catalytic cycle with minimal H(2) production, indicating slow, sequential one-electron reduction steps. Comparing the H(2)ase activity and FTIR results for the two systems showed that QDs bind more efficiently for electron transfer and that the final enzyme state is different for the two sensitizers. The possible origins of these differences and their implications for the enzymatic mechanism are discussed.
AuthorsBrandon L Greene, Crisjoe A Joseph, Michael J Maroney, R Brian Dyer
JournalJournal of the American Chemical Society (J Am Chem Soc) Vol. 134 Issue 27 Pg. 11108-11 (Jul 11 2012) ISSN: 1520-5126 [Electronic] United States
PMID22716776 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, U.S. Gov't, Non-P.H.S.)
Chemical References
  • Cadmium Compounds
  • Hydrogen
  • 3-Mercaptopropionic Acid
  • Hydrogenase
  • Tellurium
  • cadmium telluride
Topics
  • 3-Mercaptopropionic Acid (chemistry)
  • Cadmium Compounds (chemistry)
  • Catalysis
  • Catalytic Domain
  • Electron Transport
  • Hydrogen (metabolism)
  • Hydrogenase (chemistry, metabolism)
  • Light
  • Models, Molecular
  • Oxidation-Reduction
  • Photochemical Processes
  • Quantum Dots
  • Tellurium (chemistry)
  • Thiocapsa roseopersicina (enzymology)

Join CureHunter, for free Research Interface BASIC access!

Take advantage of free CureHunter research engine access to explore the best drug and treatment options for any disease. Find out why thousands of doctors, pharma researchers and patient activists around the world use CureHunter every day.
Realize the full power of the drug-disease research graph!


Choose Username:
Email:
Password:
Verify Password:
Enter Code Shown: