Related Experiment Video
Updated: Feb 21, 2026
![Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F55858.jpg&w=3840&q=50)
Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase
Published on: December 4, 2017
Difference FTIR Studies of Substrate Distribution in Triosephosphate Isomerase
Hua Deng1, Jayson Vedad2, Ruel Z B Desamero2
1Department of Biochemistry, Albert Einstein College of Medicine , Bronx, New York 10461, United States.
Triosephosphate isomerase (TIM) enzyme kinetics reveal dihydroxyacetone phosphate (DHAP) is dominant at equilibrium. Isotope-edited FTIR shows varying DHAP substates in the Michaelis complex, suggesting potential parallel reaction pathways.
Area of Science:
- Biochemistry
- Enzyme kinetics
- Spectroscopy
Background:
- Triosephosphate isomerase (TIM) interconverts DHAP and GAP via an enediol(ate) intermediate.
- Understanding TIM's reaction mechanism requires characterizing substrate populations and enzyme-substrate interactions.
Purpose of the Study:
- To determine substrate population distribution at equilibrium for TIM.
- To characterize substrate-enzyme interactions within the Michaelis complex.
Main Methods:
- Isotope-edited difference Fourier transform infrared (FTIR) spectroscopy.
- Utilized unlabeled and 13C-labeled substrates at specific carbon positions.
Main Results:
- At equilibrium, DHAP is the dominant species; GAP and enediol(ate) populations are minimal.
- DHAP within the Michaelis complex exhibits conformational substates characterized by C2═O stretch frequencies.
- Substate populations vary across different organisms' TIM enzymes.
Conclusions:
- DHAP is the predominant species at equilibrium in TIM reactions.
- Substrate activation involves C2═O bond polarization via active site hydrogen bonding.
- Observed DHAP substates suggest potential for parallel reaction pathways in TIM catalysis.
More Related Videos
13:26Determination of Protein-ligand Interactions Using Differential Scanning Fluorimetry
Published on: September 13, 2014
10:03Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy
Published on: June 27, 2014
Related Concept Videos
IR Frequency Region: Fingerprint Region
IR Spectrometers
IR Spectrum
Transmittance is defined as the ratio of the radiant power passing through a sample to that from the radiation's source. Multiplying the transmittance by 100 gives the percent transmittance (%T), which varies between 100% (no absorption) and 0%...
Enzyme Inhibition