Enzymatic reaction in water-in-oil microemulsions

✍ Scribed by Yoshikazu Miyake

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 697 KB
• Volume: 109
• Category: Article
• ISSN: 0927-7757
• DOI: 10.1016/0927-7757(95)03487-0

✦ Synopsis

The rate of the enzymatic reaction in water-in-oil microemulsions strongly depends on the water pool size, which is proportional to the ratio of the water and the surfactant concentrations, W. = [H,O]/[Sur]. The W, dependences are discussed using a reaction model which considers the solubilized loci of enzyme and substrate. A hydrophobic substrate dissolves in the organic phase and the surface layer of the microemulsions and reacts with enzyme at the surface layer. On the other hand, a hydrophilic substrate dissolves in the water pool and reacts with enzyme in the water pool. The W, dependences of the turnover number and the Michaelis constant are influenced by the hydrophobicity of the substrate, which is due to the difference in the reaction fields.

The hydrophobicity of the enzyme also affects the locus of the reaction fields. A hydrophobic enzyme such as lipase reacts with substrate at the surface layer. On the other hand, a hydrophilic enzyme such as a-chymotrypsin reacts in the water pool. The difference in the reaction field also influences the selectivity of the substrate.