Use of cyclodextrins in enzymology to enhance the solubility of hydrophobic compounds in water

In enzyme catalysis, hydrophobic compounds are usually made soluble in water by the addition of low amounts of a water-miscible organic solvent. In the present study, taking advantage of the solu-bilizing properties of inclusion compounds (cyclodextrins), a new methodology is proposed. The hydrolysis of p-nitrophenyl esters catalyzed by several hydrolases (lipase from C.cylindracea, porcine pancreatic lipase,R. arrhizus lipase and cholesterol esterase) in the presence of cyclodextrins (CD), has been investigated. This procedure presents many advantages:

1. The enzyme parameters are not affected substantially (the catalytic constant may even increase);
2. The reproducibility is higher than with previous methods;
3. CDs enhance the solubility of substrates; and
4. CDs do not destabilize enzyme structure. In some cases a thermal stabilization is observed.