The unbound proteins in the column were washed using
wash buffer (8 M urea, 100 mM NaH2PO4, 10 mM Tris–Cl, pH 6.3)
and rOmp28 protein was finally eluted from column using elution
buffer (8 M urea, 100 mM NaH2PO4, 10 mM Tris–Cl, pH 4.5).
A. Kumar et al. / Protein Expression and Purification 83 (2012) 226–232 227
Purification of rOmp28 in pET28a(+) and pQE30UA vector using Triton
X-100 and b-mercaptoethanol