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The structure and function of Saccharomyces cerevisiae proteinase A
Author(s) -
Parr Charity L.,
Keates Robert A. B.,
Bryksa Brian C.,
Ogawa Masahiro,
Yada Rickey Y.
Publication year - 2007
Publication title -
yeast
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.923
H-Index - 102
eISSN - 1097-0061
pISSN - 0749-503X
DOI - 10.1002/yea.1485
Subject(s) - saccharomyces cerevisiae , biochemistry , biology , proteinase 3 , carboxypeptidase , enzyme , proteinase k , yeast , zymogen , genetics , antibody , autoantibody
Saccharomyces cerevisiae proteinase A (saccharopepsin; EC 3.4.23.25) is a member of the aspartic proteinase superfamily (InterPro IPR001969), which are proteolytic enzymes distributed among a variety of organisms. Targeted to the vacuole as a zymogen, its activation at acidic pH can occur by two different pathways, a one‐step process to release mature proteinase A, involving the intervention of proteinase B, or a step‐wise pathway via the autoactivation product known as pseudo‐proteinase A. Once active, S. cerevisiae proteinase A is essential to the activities of other yeast vacuolar hydrolases, including proteinase B and carboxypeptidase Y. The mature enzyme is bilobal, with each lobe providing one of the two catalytically essential aspartic acid residues in the active site. The crystal structure of free proteinase A reveals that the flap loop assumes an atypical position, pointing directly into the S 1 pocket of the enzyme. With regard to hydrolysis, proteinase A has a preference for hydrophobic residues with Phe, Leu or Glu at the P1 position and Phe, Ile, Leu or Ala at P1′, and is inhibited by IA 3 , a natural and highly specific inhibitor produced by S. cerevisiae. This review is the first comprehensive review of S. cerevisiae PrA. Copyright © 2007 John Wiley & Sons, Ltd.