Establishment of the integrity of lysosomes in a glycoprotein-rich matrix. Distribution pattern of seven lysosomal enzymes in gastric mucosa.

Abstract

Gel-forming mucosal glycoproteins strongly interfere with standard methods of cell fractionation. Thus, acid hydrolase-bound particles imbedded in the gel, sediment on centrifugation, in the nuclear fraction of homogenates of canine antral mucosa. These particles can be cleared by direct solubilization of the gel; however, the viscosity of the solution obtained prevents sedimentation of some of the latent hydrolases, even at very high speeds. The use of a new step-wise scheme of centrifugation and dilution successfully isolates lysosomal particles containing acid hydrolases from mucin-rich mucosa. All of the enzymes investigated, including acid phosphatase, cathepsin D, alpha- and beta-galactosidase, beta-B-acetylhexosaminidases, but with the exception of alpha-fucosidase, were found to be particle bound, exhibiting high degrees of latency. However, active mucosal particles are polydisperase in size and density, sedimenting under different centrifugal forces.