Related Experiment Video
Updated: Aug 5, 2026
10:34
Preparation of Quality Inositol Pyrophosphates
Published on: September 3, 2011
A dual cofactor-specific isocitrate dehydrogenase from Pythium ultimum
1Department of Botany and Microbiology, Alabama Agricultural Experiment Station, Auburn University 36849, USA.
Canadian Journal of Microbiology
|December 1, 1996
Summary
Researchers purified a dual coenzyme-specific isocitrate dehydrogenase (IDH) from Pythium ultimum. This key enzyme regulates fatty acid production in microorganisms.
Area of Science:
- Biochemistry
- Enzymology
- Mycology
Background:
- Isocitrate dehydrogenase (IDH) is a critical enzyme in microbial fatty acid synthesis.
- Oleaginous microorganisms utilize IDH to convert glucose into fatty acids.
Purpose of the Study:
- To isolate and characterize a dual coenzyme-specific isocitrate dehydrogenase (EC 1.1.1.41) from the fungus Pythium ultimum.
- To understand the enzyme's role in lipid metabolism.
Main Methods:
- Purification of IDH using sequential ion-exchange, affinity, and gel filtration chromatography.
- Enzyme activity assays with NAD+ and NADP+.
- Determination of kinetic parameters (Km) and molecular mass.
Main Results:
- Achieved a 211-fold purification of IDH from Pythium ultimum.
- The enzyme exhibited higher activity with NAD+ compared to NADP+.
- Optimal activity at pH 8.5-9.5, with Km values of 0.031 mM for isocitrate and 0.55 mM for NAD+.
- Estimated molecular mass of 96 kDa (native) and 48 kDa (denaturing), indicating a dimeric structure.
- Enzyme stability up to 55°C; required Mg2+ or Mn2+ for activity.
Conclusions:
- The purified IDH from Pythium ultimum is a dimeric enzyme with dual coenzyme specificity.
- Characterization provides insights into the regulation of fatty acid biosynthesis in this primitive fungus.
- This study contributes to understanding metabolic pathways in oleaginous microorganisms.
More Related Videos
Related Concept Videos
01:15Pyruvate Oxidation
After glycolysis, the charged pyruvate molecules enter the mitochondria via active transport and undergo three enzymatic reactions. These reactions ensure that pyruvate can enter the next metabolic pathway so that energy stored in the pyruvate molecules can be harnessed by the cells.
First, the enzyme pyruvate dehydrogenase removes the carboxyl group from pyruvate and releases it as carbon dioxide. The stripped molecule is then oxidized and releases electrons, which are then picked up by NAD+...
First, the enzyme pyruvate dehydrogenase removes the carboxyl group from pyruvate and releases it as carbon dioxide. The stripped molecule is then oxidized and releases electrons, which are then picked up by NAD+...
01:46Electron Transport Chain: Complex I and II
The mitochondrial electron transport chain (ETC) is the main energy generation system in the eukaryotic cells. However, mitochondria also produce cytotoxic reactive oxygen species (ROS) due to the large electron flow during oxidative phosphorylation. While Complex I is one of the primary sources of superoxide radicals, ROS production by Complex II is uncommon and may only be observed in cancer cells with mutated complexes.
ROS generation is regulated and maintained at moderate levels necessary...
ROS generation is regulated and maintained at moderate levels necessary...
01:30The Electron Transport Chain
The electron transport chain or oxidative phosphorylation is an exothermic process in which free energy released during electron transfer reactions is coupled to ATP synthesis. This process is a significant source of energy in aerobic cells, and therefore inhibitors of the electron transport chain can be detrimental to the cell's metabolic processes.
Inhibitors of the electron transport chain
Rotenone, a widely used pesticide, prevents electron transfer from Fe-S cluster to ubiquinone or Q in...
Inhibitors of the electron transport chain
Rotenone, a widely used pesticide, prevents electron transfer from Fe-S cluster to ubiquinone or Q in...
01:41The Supercomplexes in the Crista Membrane
The mitochondrial cristae membrane is the primary site for the oxidative phosphorylation (OXPHOS) process of energy conversion mediated through respiratory complexes I to V. These complexes have been widely studied for decades, and it has been proven that they form supramolecular structures called respiratory supercomplexes (SC). These higher-order complexes may be crucial in maintaining the biochemical structure and improving the physiological activity of the individual complexes while...
01:19Allosteric Proteins-ATCase
Binding sites linkages can regulate a protein's function. For example, enzyme activity is often regulated through a feedback mechanism where the end product of the biochemical process serves as an inhibitor.
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
01:43Electron Transport Chain: Complex III and IV
During the electron transport chain, electrons from NADH and FADH2 are first transferred to complexes I and II, respectively. These two complexes then transfer the electrons to ubiquinol, which carries them further to complex III. Complex III passes the electrons across the intermembrane space to Cyt c, which carries them further to complex IV. Complex IV donates electrons to oxygen and reduces it to water. As electrons pass through complexes I, III, and IV, the energy released aids the pumping...