Kinetic-mechanistic studies of P. cepacia lipase catalyzed corona charge selective micelle degradation

Polymers with a polyester hydrophobic end (poly(caprolactone)) and a polyether hydrophilic end (poly(ethylene oxide)) self-assemble into spherical micelles. These micelles can be modified at the surface by placing a neutral or charged group at one end of the polymer. An enzyme called lipase from Pseudomonas cepacia degrades the polymer at the hydrophobic core. Six isoforms of P. cepacia lipase were identified, falling into two classes according to their ability to degrade micelles with positively or negatively charged corona. These isoforms were physically separated according to their different isoelectric points. The findings suggest that the variation of micelle surface charge could be employed as a strategy in the design of micelles for selective transport and release of therapeutic substances.