FIG. 4.
(A) Purification of recombinant C. jejuni serine dehydratase. Lane 1, molecular mass markers (phosphorylase B, 97 kDa; bovine serum albumin, 66 kDa; ovalbumin, 45 kDa; carbonic anhydrase, 31 kDa; soybean trypsin inhibitor, 21.5 kDa; and lysozyme, 14.4 kDa). Lane 2, 15 μg of cell extract protein from BL21(DE3 pLysS pJV12) after IPTG induction for 5 h. Lane 3, purified l-serine dehydratase (3 μg) following chromatography on nickel-nitrilotriacetic acid resin. (B) Determination of the native molecular weight of purified SdaA by gel filtration on Superdex-200. The column was calibrated by using thyroglobulin (669 kDa), horse spleen apoferritin (443 kDa), sweet potato amylase (200 kDa), yeast alcohol dehydrogenase (150 kDa), bovine serum albumin (66 kDa), and bovine erythrocyte carbonic anhydrase (29 kDa). Ve, protein elution volume; Vo, column void volume (as determined with blue dextran).