Generation of Dipeptidyl Peptidase-IV-Inhibiting Peptides from β-Lactoglobulin Secreted by Lactococcus lactis

Figure 4

Purification of rBLG secreted by NZ9000. Expression of rBLG by NZ9000 was induced in a 4 L large-scale culture. The cell extract (crude lysate) was prepared as described in Section 2 and then passed through a HisTrap HP column (flow-through). The column was washed to remove nonadsorbed protein (wash) and then eluted (elution) with wash buffer containing 20 mM imidazole and elution buffers containing 31 to 500 mM imidazole. All fractions were analyzed by Western blotting with a 6x His-tag Ab. White and black arrowheads indicate the secretory rBLG precursor (pre-rBLG, 27 kDa) and the secretory form of rBLG (24.3 kDa), respectively.