FIG. 5.
BFT copurifies with carbohydrate molecules. (A) Western blot of the proteinase K digestion of BFT-2. Using polyclonal anti-BFT-2 sera (1/1,000 dilution), only higher-molecular-mass bands were detected in BFT-2 purified by the Van Tassell method after digestion with proteinase K (50 μg/ml, 60 min, 37°C) (lane 1). After SDS-PAGE fractionation, Coomassie blue staining of BFT-2 treated with proteinase K revealed no bands (data not shown). Lane 2 shows the appearance of the BFT-2 preparation prior to proteinase K digestion. Each lane was loaded with 70 ng of protein. (B) Western blot of BFT-2 treated with sodium metaperiodate. Lane 1, BFT-2 treated with 10 mM sodium metaperiodate as described in Materials and Methods; lane 2, untreated BFT-2. Immunostaining was performed using polyclonal anti-BFT-2 sera (1/1,000 dilution).