SDS-PAGE gel of fractions of uninduced and induced E. coli BL21(DE3) cells carrying pEXL1. Lane 1, uninduced cells, total cell protein; lane 2, induced cells, cell extract (soluble fraction); lane 3, induced cells, cell extract (insoluble fraction; the relative amount loaded is 1/10 of that loaded in lanes 1 and 2); lane 4, native purified xanthan lyase; lane 5, marker proteins (phosphorylase b, 94 kDa; bovine serum albumin, 67 kDa; ovalbumin, 43 kDa); lane 6, Bio-Rad precision protein standards.