Fig. 5.

Soluble and membrane-associated endopeptidase 3.4.24.16 activity during differentiation of primary cultured neurons.A, Primary cultured neurons were scraped at the indicated differentiation times in 5 mm Tris-HCl, pH 7.5, and subcellular fractions were prepared as described in Materials and Methods. Both soluble (white bars) and membrane-associated (black bars) fractions were tested for their QFS-hydrolysing activities as described in Materials and Methods.B illustrates the ratio between QFS-hydrolysing activity in membrane-associated versus soluble fractions according to differentiation time. C, Five micrograms of membrane-associated fractions taken at 1, 3, 5, and 7 d of culture were dried, submitted to an 8% acrylamide gel, and analyzed by Western blot with the anti-E 3.4.24.16 IgG fraction as described in Materials and Methods.