Overview
Thiolase (EC 2.3.1.16) is a fundamental enzyme in fatty acid β-oxidation and biosynthetic pathways, particularly in polyhydroxyalkanoate (PHA) production. It catalyzes the reversible cleavage of 3-ketoacyl-CoA into acetyl-CoA units, a critical step in both catabolic and anabolic processes. Bacterial thiolases are widely studied for their robust catalytic properties and thermostability, making them valuable in industrial biotechnology. First characterized in Clostridium species, thiolases exist in multiple forms across prokaryotes and eukaryotes. Their conserved active site structure features a catalytic cysteine residue that forms a thioester intermediate during the reaction mechanism. Modern genetic engineering techniques have enabled the production of recombinant thiolases with enhanced activity for commercial applications.
Physical and Chemical Properties
Bacterial thiolases typically function as homotetramers with subunits ranging from 380-420 amino acids. The enzyme demonstrates optimal activity at pH 7.5-8.5 and temperatures between 30-45°C, though thermophilic variants remain stable up to 60°C. Kinetic studies show Km values in the micromolar range for acetyl-CoA substrates. Structural analysis reveals a characteristic TIM barrel fold with two binding pockets: one for the acyl-CoA substrate and another for the CoA-SH nucleophile. The enzyme requires divalent cations (Mg²⁺ or Mn²⁺) for stabilization of the transition state. Commercial preparations often contain stabilizing agents like glycerol (10-50%) to prevent aggregation during storage.
Main Applications
In industrial biotechnology, thiolase is crucial for producing biodegradable plastics (PHAs) through microbial fermentation. Companies like Danimer Scientific and Tianjin GreenBio Materials utilize engineered thiolase pathways to convert plant oils into PHA polymers. The enzyme also enables biosynthesis of pharmaceutical precursors like (R)-3-hydroxybutyrate. Metabolic engineering applications include designing synthetic pathways for biofuel production (e.g., butanol) and fine chemicals. Researchers have developed E. coli strains with amplified thiolase activity to improve yields in isopropanol and acetone production. Diagnostic kits incorporate thiolase for detecting metabolic disorders related to ketone body metabolism.
Safety and Storage
While thiolase presents low acute toxicity, inhalation of lyophilized powder may cause respiratory irritation. Recommended PPE includes nitrile gloves and safety goggles when handling concentrated solutions. Spill management involves absorption with inert material and disposal as biological waste. For optimal stability, lyophilized enzyme should be stored at -20°C in airtight containers with desiccant. Liquid formulations typically contain 25-50% glycerol as cryoprotectant. Avoid repeated freeze-thaw cycles, which can reduce activity by up to 30% per cycle. Activity assays should verify enzyme potency before critical applications.
B2B Procurement Guide
Industrial buyers should specify activity units (μmol/min/mg) rather than mass alone when purchasing thiolase. Pharmaceutical-grade material requires certificates of analysis (CoA) documenting <0.1 EU/mg endotoxin levels. Bulk orders (100+ grams) from manufacturers like Sigma-Aldrich or Codexis typically offer 15-30% cost reductions. Key evaluation criteria include thermostability (especially for fermentation applications), absence of protease contaminants, and batch-to-batch consistency. Custom engineering services are available for creating mutant thiolases with altered substrate specificity. Logistics planning must account for cold chain requirements—dry ice shipment is recommended for international orders.
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