Fig. 4. PMPs are not associated with membranes in pex3Δ and pex19Δ cells. The 2500 g supernatant fraction (S1) prepared from pex3Δ, pex6Δ or pex19Δ cells was adjusted to 55% (w/v) sucrose, layered on top of a 60% sucrose cushion and under a 25–46% sucrose gradient and spun for 18 h at 100 000 g. Fractions obtained from these gradients were analysed by immunoblotting using the antibodies directed against the proteins indicated. Endosomal membrane marker, Tlg1p; cytosolic marker, hexokinase (HK); peroxisomal membrane markers are Pat1p and Pex15p. Fraction 1, bottom; fraction 12, top. Note that the S1 load is located in fractions 2–6 in pex3Δ and in fractions 2–7 in pex6Δ and pex19Δ. Fraction 1 corresponds to the 60% sucrose cushion.