LIPOPROTEIN-LIPASE IMMOBILIZATION ONTO COPOLY(ETHYLENE ACRYLIC-ACID) FIBER

A water-insoluble enzyme was prepared by immobilizing lipoprotein lipase (LPL) onto the surface of the copoly(ethylene/acrylic acid) fine fiber by covalent fixation. The relative activity (RA) of the immobilized LPL was found to remain high toward small ester substrates, p-nitrophenyl laurate (pNPL). LPL immobilized with spacer gave an almost constant RA in marked contrast with the immobilized LPL without spacer whose RA monotonous decreased with the decreasing surface concentration of the immobilized LPL on the copolymer fiber. The Michaelis constant K(m) and the maximum reaction velocity V(m) were estimated for the free and the immobilized LPL. The apparent K(m) was larger for the immobilized LPL than for the free one, while V(m) was smaller for the immobilized LPL. The pH, thermal and storage stabilities of the immobilized LPL were higher than those of the free ones. The initial enzymic activity of the immobilized LPL maintained almost unchanged without any leakage and inactivation of LPL when the batch enzymic reaction was performed repeatedly, indicating excellent durability of the immobilized LPL.