Purification and identification of rAc-cathB-1. (A) Purification of rAc-cathB-1 from the cell culture supernatant. Lanes: MW, molecular weight markers (listed in kDa on the side); 1, concentrated culture supernatant in binding buffer; 2, column flowthrough; 3, binding buffer wash; 4–6, successive eluate fractions (during the elution step, the eluate was collected in one 5 ml tube after another); 7, eluate from gel filtration. (B) Identification of purified rAc-cathB-1 by western blot with an antiserum against Ac-cathB-1 expressed in E. coli and an anti-Myc antibody.