An immobilized microbial heparinase for blood deheparinization.
A new medical application of an immobilized microbial enzyme is described. Extracorporeal devices require systemic heparin administration to prevent thrombus formation; however, the use of heparin often leads to serious hemorrhagic complications. Heparinase isolated from Flavobacterium has been immobilized and used in a fluidized bed reactor to eliminate heparin from blood passing through an extracorporeal circuit both in vitro and in vivo. This paper discusses the stepwise development of this heparinase reactor including: (1) improvements in the fermentation resulting in an inexpensive large-scale source of heparinase without the addition of the previously required inducer, heparin; (2) the use of batch processes to adapt previous purification schemes to large-scale heparinase production and the subsequent purification of heparinase to a single SDS-PAGE banding protein; (3) the immobilization of heparinase with a 91% activity recovery and good stability, (4) the design and successful testing of a fluidized bed reactor containing immobilized heparinase in the removal of clinically used quantities of heparin from both human blood in vitro and canine blood in vivo; and (5) the initiation of animal studies focusing on the toxicology of heparinase-derived heparin degradation products and the short and long term effects of exposure to these products and to heparinase.
D004800:Enzymes, Immobilized / Q000378:metabolism / Q000627:therapeutic use*; D005285:Fermentation; D005417:Flavobacterium / Q000302:isolation & purification; D006493:Heparin / Q000097:blood*; D019763:Heparin Lyase; D006801:Humans; D007700:Kinetics; D011133:Polysaccharide-Lyases / Q000302:isolation & purification / Q000378:metabolism / Q000627:therapeutic use*
D004800:Enzymes, Immobilized; D006493:Heparin; D011133:Polysaccharide-Lyases; D019763:Heparin Lyase