Intracellular degradation of newly synthesized apolipoprotein B

Degradation of newly synthesized collagen.

Explants of rabbit lung parenchyma maintained in serumfree medium incorporate I 14Clproline and I Wllysine into collagen as I “Clhydroxyproline and I Wlhydroxylysine at a constant rate for at least 24 h. Evaluation of the size distribution of the [14Clhydroxyproline and [‘4Clhydroxylysine containing peptides within the explants demonstrated that 20 to 40% of the LY chains of newly synthesized c...

Intracellular Cleavage of Newly Synthesized Low Affinity

Regulation of the production of secretory proteins: intracellular degradation of newly synthesized "defective" collagen.

Confluent cultures of human fetal lung fibroblasts degrade approximately 10% of their newly synthesized collagen within the cell prior to secretion. This basal level of intracellular degradation could not be inhibited by colchicine or cytochalasin B, inhibitors of microtubular and microfilament function, respectively, or by N(alpha)-p-tosyl-L-lysine chloromethyl ketone, chloroquine, or NH(4)Cl,...

Association of newly synthesized islet prohormones with intracellular membranes

Results from recent studies have indicated that pancreatic islet prohormone converting enzymes are membrane-associated in islet microsomes and secretory granules. This observation, along with the demonstration that proglucagon is topologically segregated to the periphery within alpha cell secretory granules in several species, led us to investigate the possibility that newly synthesized islet p...

Intracellular degradation in the regulation of secretion of apolipoprotein B-100 by rabbit hepatocytes.

Isolated rabbit hepatocytes were incubated with [35S]methionine to label intracellular pools of apolipoprotein B (apo-B). The cells were then reincubated with an excess of unlabelled methionine in the presence of oleate or protease inhibitors and the intracellular sites of accumulation of radiolabelled apo-B and the mass of apo-B were determined by isolation and analysis of subcellular fraction...