at 7.3 minutes. Another experiment involved a 60-minute incubation performed with 100 CLM TCPM and 0.1 mg cytosolic protein from polar bear, channel catfish and human liver. For each of the three species, we detected a conjugate at Rf = 0.54. The substrate blanks showed no band at the same position (Figure 3-6). The TCPM sulfate conjugate from polar bear could be hydrolyzed by sulfatase (Figure 3-7), providing further evidence of the sulfonation of this alcohol. A B 12 34 Figure 3-7. Autoradiogram showing the reverse-phase TLC separation of sulfonation products of TCPM and the effect of sulfatase treatment. A, incubation in the absence of TCPM (lane 1), and following treatment with sulfatase (lane 2). B, incubation with 200 CLM TCPM (lane 3), and following treatment with sulfatase (lane 4). The arrow indicates the sulfate conjugate of the TCPM, while other bands represent unidentified sulfate conjugates formed from endobiotics or other xenobiotics in polar bear liver cytosol. Inhibition of sulfonation of substrates already present in the polar bear liver was noted upon adding 1 CLM PCP (Figure 3-8). The data for PCP sulfonation fitted the nonlinear Hill plot (eq. 2) (Table 3-2).