5-17 Kyte-Doolittle Hydrophobicity Plot for liv/intUGTp .............. .....................0

5-18 Results of NCBI conserved domain search for I35R Cp .............. ...................103

5-19 Alignment of predicted protein sequences from cloned catfish UGTs. Regions of
 interest and the starting and ending residue of the mature product are
 highlighted. ........... ..... ._ ...............104...

5-20 Cloning of livUGTn. ..........._.....__ .....__ .....__ ........... ....105

5-21 Cloning of intUGTn. ..........._.....__ .....__ .....__ ........... ....105

5-22 Multiple sequence alignment for fish sequences homologous to catfish UGT
 isolated from liver and intestine, showing regions where substrate binding of
 phenols is thought to occur for mammalian UGTI1A isozymes. ................... .........110

5-23 Results of 3' RACE performed on liver, showing multiple products obtained...... 111

5-24 3' RACE for I4. ................ ...............112..............

5-25 PCR amplification of UGT using degenerate primers. ........._._ ... ......_._.......1 14

6-1 Heat-induced degradation of UDPGA (boiling in 0.25 M H2PO4 buffer) ............120

6-2 Decomposition of UDPGA to UDP and UMP after boiling in 0.25 M H2PO4
 buffer for 10 minutes ..........._ _..... .._ ...............120.

6-3 Effect of boiling liver tissue for 1 minute in two different concentrations of
 buffer. A, 0.25 M H2PO4, pH 3.4; B, 0.30 M H2PO4, pH 4.3 ................ ............... 121

6-4 HPLC chromatogram for catfish AT17 liver. Center refers to region of liver
 from which the sample was taken. ............. ...............122....

6-5 HPLC chromatogram for catfish AT18 intestine. Rep 2 refers to second sample
 taken from AT18 intestine. .........__ _............ ...............123.

6-6 HPLC chromatogram of UDP, UDP-galacturonic acid (UDPGTA), and UDPGA
 standards ................. ...............125................

6-7 Comparison of hepatic and intestinal [UDPGA] in 4 individual channel catfish. .126