I PBK
 SPB X











 0 100 200 300 4100 500 600 700 800


 [4'-OH-PCB79] (CLM)


Figure 3-4. Sulfonation of 4'-OH-PCB79, PAPS = 0.02 mM.

 Each data point represents the average of duplicate assays for each bear, while
 the error bars represent the standard deviation. The line represents the best fit
 to equation (4) for 4'-OH-PCB79.


 Due to variable rates of sulfonation of these unknown substrates, autoradiographic

counts corresponding to the OHMXC-O-sulfate band were used to correct the activities

calculated from the scintillation counter data (Figure 3-5). This enabled the transformed

data to be fit into a Michaelis-Menten model (Table 3-2). The autoradiograms obtained

showed that increasing concentrations of OHMXC resulted in decreased counts for the

unknown sulfate conjugates (Figure 3-5). Sulfonation of the unknown substrates in polar

bear cytosol was reduced by half at OHMXC concentrations < 20 LM.