title: The synthesis of L-tryptophan degrading bioreactors.
abstract: To design a bioreactor for removing the potential cancer nutrient L-tryptophan from blood, the L-tryptophan degrading enzyme tryptophan side chain oxidase (TSO) was chemically bound to glutaraldehyde activated gamma amino silane silica and to Zetaffinity microcolumns consisting of a glutaraldehyde activated polyacrylic-cellulose copolymer. Five experiments were carried out in sheep and six experiments in rabbits using a closed circuit plasmapheresis bioreactor system. L-tryptophan in sheep was degraded by the silica bioreactor in a single pass to undetectable levels as measured by high performance liquid chromatography (HPLC). Zetaffinity bioreactors degraded L-tryptophan in rabbits to more than 95% in a single pass. Whole blood L-tryptophan levels changed little throughout the experiment indicating a vast extravascular tryptophan pool. Enzyme leakage from the bioreactor was less than 10(-5) IU TSO per ml plasma. The procedures were tolerated well by the animals without any change in vital signs.
authors.affiliation: Department of Laboratory Medicine, University of Washington, Seattle.
authors.forename: G
authors.initials: G
authors.lastname: Schmer
authors.forename: M B
authors.initials: MB
authors.lastname: Dennis
authors.forename: S
authors.initials: S
authors.lastname: Hsueh
authors.forename: K C
authors.initials: KC
authors.lastname: Hou
mesh_terms: D000818:Animals; D005976:Glutaral; D006899:Mixed Function Oxygenases / Q000378:metabolism; D010956:Plasmapheresis / Q000379:methods*; D011817:Rabbits; D012756:Sheep; D012822:Silicon Dioxide; D014364:Tryptophan / Q000097:blood / Q000378:metabolism*
chemical_list: D012822:Silicon Dioxide; D014364:Tryptophan; D006899:Mixed Function Oxygenases; C021442:indolyl-3-alkane-alpha-hydroxylase; D005976:Glutaral