Secretion and pH-dependent self-processing of the pro-form of the Yarrowia lipolytica acid extracellular protease.
The secretion and maturation of the acid extracellular protease (AXP) of the yeast Yarrowia lipolytica have been characterized using antiserum raised against this enzyme. A 42 kDa pro-enzyme form of AXP was identified from lysates of radiolabelled Y. lipolytica cells and found to contain no N-linked carbohydrate moieties. Using pulse-chase immune precipitation it was demonstrated that the AXP precursor was secreted into the extracellular medium where, under conditions of low pH, it underwent autocatalytic activation forming the mature enzyme. Conversion of the AXP pro-form in the presence of the protease inhibitor pepstatin indicated that an intramolecularly-catalysed reaction mechanism was involved in AXP maturation. Further evidence supporting the role of autocatalytic processing came from the side-chain specificity of mature AXP towards the oxidized B-chain of insulin.
School of Biochemistry, University of Birmingham, UK.
R K
RK
McEwen
T W
TW
Young
D000595:Amino Acid Sequence; D016282:Aspartic Acid Endopeptidases / Q000235:genetics / Q000378:metabolism*; D017077:Culture Media, Conditioned / Q000737:chemistry / Q000378:metabolism; D004792:Enzyme Precursors / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins; D006863:Hydrogen-Ion Concentration; D007930:Leucine / Q000378:metabolism; D008969:Molecular Sequence Data; D011233:Precipitin Tests; D011499:Protein Processing, Post-Translational; D013379:Substrate Specificity; D014316:Tritium; D015003:Yeasts / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics
D017077:Culture Media, Conditioned; D004792:Enzyme Precursors; D005656:Fungal Proteins; D014316:Tritium; C103006:AXP protein, Yarrowia lipolytica; D016282:Aspartic Acid Endopeptidases; D007930:Leucine