Biosynthesis of low density lipoprotein by cell-free preparations of rat intestinal mucosa.

摘要: Abstract The capacity of cell-free preparations rat small intestinal mucosa to synthesize and release lipoproteins was investigated. Palmitate-1-14C administered intragastrically 30 min later labeled fractions from homogenates were prepared. (whole homogenate, mitochondria, microsomes) incubated in fortified media containing 3H-labeled amino acids, various densities separated, after the addition carrier plasma, by density centrifugation, polyanion precipitation, immunoprecipitation. All incorporated radioactivity into lipid protein moieties medium lipoproteins. activity microsomal fraction accounted for most whole homogenate. Presence postmicrosomal supernatant or pH 5 fraction, GTP, ATP, ATP-generating system essential optimal fraction. ratio 14C:3H (solubilized LiCl) low lipoprotein (LDL) isolated ultracentrifugation, precipitation with polyanions, immunoprecipitation remained within reasonably narrow limits. identity LDL that plasma demonstrated immunoelectrophoresis, double immunodiffusion, peptide mapping. results indicate cellular equivalent may be major site synthesis association LDL. They further contribute significantly level through incorporation apoprotein chylomicrons very it can central importance transport exogenous endogenous lipid.