from a sephadex u00ae g50 column the sulfhydryl containing bbi fractions which eluted at the column void volume were identified using elman 39 s reagent and then reacted with a 3 fold excess per sulfhydryl group on bbi of pal pdc v in pbs ph 7 0 for 16 hrs at 4 u00b0 c the reaction mixture was then acidified to ph 3 0 using hci 1m and left on ice for 30 min the supernatant was analyzed separately using a sephadex g25 gel filtration column the precipitate which contained the palmityl disulfide conjugate of bbi bbisspal vi and the excess reagent was isolated by centrifugation dissolved in dmf 2 ml and eluted from a sephadex u00ae lh20 column using dmf bbisspal vi fractions which eluted at column void volume were isolated dialyzed 3 times against 500 volumes of water and then lyophilized the yield of the conjugate using this procedure was approximately 80 by weight the conjugation of pal pdc to bbi was confirmed and quantitated after the conjugation of 3h labeled pal pdc v to bbi using identical conjugation conditions as the ones described above also using an identical procedure the oleic acid conjugated bbi bbissoleic was synthesized human colon carcinoma cells caco 2 were detached from 25 cm 2 stock culture flasks using a 10 min incubation at 37 u00b0 c with 0 5.