FIG. 3.

Gel filtration of periplasmic fractions on Superdex 75HR and analysis of the collected fractions on a Western blot with anti-FLAG M2. (A) Chromatogram, obtained by plotting A₂₈₀ against the fraction number, illustrating the separation of the periplasmic proteins from clone D2. The retention times of the marker proteins are indicated with arrows. (B) Western blot analysis (15% gel) of the collected fractions (fraction number is shown above the blots) obtained from gel filtration of anti-p24 clones and of an anti-hCG scFv-producing clone. Two peak fractions can be discriminated in the scFvs having a complete linker (the derivative D2/15 and the anti-hCG): a main peak of the monomer (fraction 20; molecular mass, 25 kDa) and a dimer peak (fraction 17; molecular mass, 45 kDa). scFv of clone D2 emerged from the column in a single peak corresponding to the dimeric product.