pH-dependent processing of yeast procarboxypeptidase Y by proteinase A in vivo and in vitro
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Carboxypeptidase Y is a vacuolar enzyme from Saccharomyces cerevisiae. It enters the vacuole as a zymogen, procarboxypeptidase Y, which is immediately processed in a reaction involving two endoproteases, proteinase A and proteinase B. We have investigated the in vitro activation of purified procarboxypeptidase Y by purified proteinase A. This has identified two different processing intermediates; one active and one inactive. The intermediates define a 33 amino acid segment of the 91 amino acid propeptide as sufficient for maintaining the enzyme in an inactive state. The inactive intermediate was isolated from a processing reaction at neutral pH. In order to investigate the influence of vacuolar pH on processing in vivo, the autoactivation of proteinase A and its processing of procarboxypeptidase Y were studied in a vma2 prb1 mutant, which is deficient in vacuolar acidification and proteinase B activity. Efficient processing of procarboxypeptidase Y in the absence of proteinase B is dependent on acidic vacuolar pH, and the processing at neutral pH is slow and takes place in two steps similar to those identified in vitro.
Original language | English |
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Journal | European Journal of Biochemistry |
Volume | 220 |
Issue number | 1 |
Pages (from-to) | 19-27 |
Number of pages | 9 |
ISSN | 0014-2956 |
Publication status | Published - 1994 |
- Amino Acid Sequence, Aspartic Acid Endopeptidases, Binding Sites, Carboxypeptidases, Cathepsin A, Enzyme Activation, Enzyme Precursors, Genes, Fungal, Hydrogen-Ion Concentration, Molecular Sequence Data, Mutation, Protein Processing, Post-Translational, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Serine Endopeptidases, Vacuoles
Research areas
ID: 43974456