The synthesis of L-tryptophan degrading bioreactors.
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.
Schmer
G
G
Department of Laboratory Medicine, University of Washington, Seattle.
Dennis
M B
MB
Hsueh
S
S
Hou
K C
KC
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*
D012822:Silicon Dioxide; D014364:Tryptophan; D006899:Mixed Function Oxygenases; C021442:indolyl-3-alkane-alpha-hydroxylase; D005976:Glutaral