title: Involvement of proteasomes (multicatalytic proteinase) in ATP-dependent proteolysis in rat reticulocyte extracts.
abstract: The role of proteasomes, particles with latent multicatalytic proteinase, in ATP-dependent proteolysis in rat reticulocyte extracts was examined. Removal of proteasomes from the extracts by immunoprecipitation caused almost complete inhibition of ATP-dependent degradation of [3H]methylcasein, without affecting ATP-dependent proteolysis. Peptide fragments of [3H]casein, obtained by cyanogen bromide cleavage, were rapidly degraded in an ATP-independent fashion and this activity was not affected by removal of the proteasomes. These results suggest that proteasomes are involved in ATP-dependent proteolysis in the extracts and that they catalyze the initial cleavage of large proteins.
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D002364:Caseins / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D005934:Glucagon / Q000378:metabolism; D007118:Immunoassay; D007328:Insulin / Q000378:metabolism; D009097:Multienzyme Complexes / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex; D051381:Rats; D011919:Rats, Inbred Strains; D012156:Reticulocytes / Q000201:enzymology*
chemical_list: D002364:Caseins; D007328:Insulin; D009097:Multienzyme Complexes; D010446:Peptide Fragments; D000255:Adenosine Triphosphate; D005934:Glucagon; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex