Abstract: Compositions containing two species of indolyl-3-alkane alpha-hydroxylase (INDH) are isolated from Pseudomonas XA. An INDH1 composition contains protein subunits having molecular weights of 75,000, 34,500 and 32,500 daltons. An INDH2 composition contains protein subunits having molecular weights of 60,000, 44,000 and 42,000 daltons. Molecular weights are determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The compositions have a Specific INDH Activity of at least 10 international Units of INDH activity per milligram of protein, and contain less than 1 nanogram of endotoxin per International Unit of Specific INDH Activity. The INDH compositions may be immobilized on an insoluble matrix such as silica beads to provide at least 2.5 international Units of INDH activity per gram of Immobilized INDH composition. The INDH compositions are isolated by lysing Pseudomonas XA cells at a temperature of no more than 15.degree. C.

Abstract: A culture of Pseudomonas XA cells containing indolyl-3-alkane alpha-hydroxylase(INDH) is produced by aerobic batch fermentation in a culture medium. The culture medium is in a vessel having a means for adjusting agitation rate. During culturing, the cells go through a logarithmic phase and a stationary phase. Oxygen concentration is measured in the culture medium at the beginning of the process to determine a first oxygen concentration. Agitation rate is adjusted to produce a second oxygen concentration in the culture medium of about two to about seven percent of the first oxygen concentration for a time period of about two to about seven hours which ends at the beginning of the stationary phase. An INDH having three subunits of different molecular weight is isolated from the cells. The INDH is stable, free from endotoxin-mediated side effects and has sufficient specific activity to be useful for depletion of tryptophan from aqueous solution. During use, the INDH may be in immobilized form.