Enzymatic Detoxification Using Lipophilic Hollow‐Fiber Membranes: I. Glucuronidation Reactions

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Abstract
A lipophilic hollow-fiber membrane preparation was used in the enzymatic detoxification of lipophilic toxins. Native enzymes were circulated on one side of the lipophilic membrane, while the toxin-containing media (blood, serum, waste fluids, etc.) were circulated inside the hollow fiber. Lipophilic substances that accumulate in and penetrate the lipophilic membrane were converted by the corresponding enzymes. Phase II detoxifying enzymes converted the lipophilic toxins to hydrophylic compounds that made a rediffusion of these molecules back to the blood impossible. Glucuronidation reactions were catalyzed by a crude preparation of solubilized uridine-5′-diphosphate-glucuronyltransferase (EC 2.1.1.9) with a specific activity of 10.0 nmol/min/mg protein in the presence of uridine-5′-diphosphoglucuronic acid (acceptor: phenol as reference substrate). Clearance rates of phenol, 1-naphtol, 2-naphtol, and p-cresol were measured, respectively, to be 141, 195, 300, and 251 pmol/ h/mg protein/cm2 hollow fiber. The advantage of this technique lies in the possibility of using highly active, soluble enzyme preparations and a fully utilizable cofactor supply. The lipid membrane ensures the absence of immunological hazards, while mass transfer of the toxin is not impaired.