title: Mammalian signal peptidase: partial purification and general characterization of the signal peptidase from microsomal membranes of porcine pancreas.
abstract: Signal peptidase has been enriched extensively from microsomal membranes of porcine pancreas. Microsomal membranes were washed with 1 M KCl and Brij 35, and then solubilized with 1% Nonidet P-40. The solubilized signal peptidase was purified by DEAE-cellulose chromatography and Sepharose CL-6B filtration. Cleavage of pre-human placental lactogen with the partially purified enzyme gave the mature form, whose NH2-terminus was identified as valine. The signal peptidase is heat-labile and approximately 90% of the enzymatic activity was lost at 60 degrees C within 1 min. The pH optimum of the activity was 7 to 8. Chymostatin and o-phenanthroline at concentrations of 2.5 mM inhibited the signal peptidase activity by 62% and 30%, respectively.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D010450:Endopeptidases / Q000302:isolation & purification* / Q000378:metabolism; D005260:Female; D006801:Humans; D007425:Intracellular Membranes / Q000201:enzymology*; D007700:Kinetics; D008565:Membrane Proteins; D008861:Microsomes / Q000201:enzymology*; D010179:Pancreas / Q000201:enzymology*; D010920:Placenta / Q000378:metabolism; D011061:Poly A / Q000235:genetics; D011247:Pregnancy; D011499:Protein Processing, Post-Translational; D012313:RNA / Q000235:genetics; D012333:RNA, Messenger; D012697:Serine Endopeptidases; D013552:Swine
chemical_list: D008565:Membrane Proteins; D012333:RNA, Messenger; D011061:Poly A; D012313:RNA; D010450:Endopeptidases; D012697:Serine Endopeptidases; C026515:type I signal peptidase