Association of alpha- and beta-subunits during the biosynthesis of beta-hexosaminidase in cultured human fibroblasts.

摘要: Subunit association of beta-hexosaminidase was studied in intact fibroblasts using antisera that discriminate between free and associated alpha-chains. These were anti-beta-hexosaminidase A (anti-alpha beta), which precipitated all alpha-chains, or associated; B (anti-beta those alpha-chains with beta; anti-alpha-chains, recognized only monomeric After biosynthetic labeling, its alpha-subunit immuno-precipitated from extracts cells medium the aid protein A-bearing Staphylococcus aureus, subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis, visualized by fluorography. Pulse-chase labeling showed existed predominantly precursor form during first 5 h, then began accumulate mature (lysosomal) alpha beta form. Precursor complexes secreted, along some monomers; latter catalytically inert. Both alpha- beta-chains phosphorylated (a Golgi modification) prior association. Thus alpha-beta probably occurred area before transfer lysosomes secretion. Cycloheximide inhibited subsequent maturation preformed perhaps causing a depletion pool beta-chain upstream site subunit In patient Sandhoff disease, produced no beta-chains, self-associated but their markedly decreased. We suggest is necessary not for acquisition catalytic activity also transport lysosomes.