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Implantable hollow fiber bioreactor as a potential treatment for hypercholesterolemia: Characterization of the catalytic unit
Author(s) -
Shefer Samuel D.,
Rosenberger Vered,
Vahanian Gizette,
Wong Wai T.,
Langer Robert
Publication year - 1995
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260480107
Subject(s) - characterization (materials science) , bioreactor , fiber , unit (ring theory) , materials science , catalysis , biomedical engineering , chemistry , nanotechnology , chemical engineering , medicine , engineering , organic chemistry , composite material , psychology , mathematics education
Previous studies have shown that the modification of low density lipoprotein (LDL) by the enzyme phospholipase A 2 (PLA 2 )results in a reduction of cholesterol levels in the plasma of hypercholesterolemic rabbits, due to accelerated clearance of the modified LDL. In the current study, we established techniques and optimized the ratio of enzyme to support for the immobilization of PLA 2 on a polymeric support. Hollow fiber bioreactors made from polytetrafluoroethylene (PTFE) polymers were used to encapsulate immobilized PLA 2 . This design was adopted to eliminate hemolysis of red blood cells by the enzyme. Characterization of the resulting immobilized enzyme in terms of its activity, Michaelis‐Menten kinetic constants, and the variation of its activity with incubation time is presented. The enzyme activity was not significantly altered upon incubation at 37°C in lipoprotein‐deficient serum (LPDS), over the course of 2 months. The Michaelis–Menten kinetics constants are K M = 8.9 m M , V max = 6434.2 for the free enzyme and K app M= 16.7 m M , V app max= 619.7 for the immobilized enzyme. These data suggest that a system based on immobilized PLA 2 in conjunction with hollow fiber bioreactors (HFBs) may be a good candidate for lowering LDL levels in plasma. © 1995 John Wiley & Sons, Inc.