Rat liver microsomal palmitoyl-coenzyme A synthetase. Structural properties

Area of Science:

• Biochemistry
• Enzymology
• Molecular Biology

Background:

• Palmitoyl-CoA synthetase is crucial for fatty acid metabolism.
• Understanding its structure is key to elucidating its function.
• Microsomal enzymes often exist in complex, associated forms.

Purpose of the Study:

• To investigate the structural properties of purified palmitoyl-CoA synthetase.
• To determine the molecular weight and quaternary structure of the active enzyme.
• To assess the role of phospholipids and fatty acids in enzyme structure and activity.

Main Methods:

• Purification of palmitoyl-CoA synthetase from rat liver microsomal material.
• Molecular weight determination using ultracentrifugation or gel filtration.
• Analysis of bound phospholipids and fatty acids.
• Investigation of enzyme association under various conditions.

Main Results:

• The active palmitoyl-CoA synthetase has a molecular weight of 168,000 Daltons.
• The enzyme is associated with approximately 8.2 moles of phospholipid per mole of enzyme protein.
• Bound fatty acids were also detected.
• Enzyme association was observed to occur without impairing catalytic activity.
• The smallest subunit identified under denaturing conditions had a molecular weight of 27,000 Daltons.

Conclusions:

• Palmitoyl-CoA synthetase exists as a large, oligomeric complex in its active form.
• Phospholipids and fatty acids are integral components of the enzyme's structure.
• The enzyme's ability to associate is critical for its function and stability.