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Assembly of amine oxidase and D ‐amino acid oxidase in the cytosol of peroxisome‐deficient mutants of the yeast Hansenula polymorpha during growth of cells on glucose in the presence of primary amines or D ‐alanine as the sole nitrogen source
Author(s) -
Sulter G. J.,
Van Der Klei I. J.,
Harder W.,
Veenhuis M.
Publication year - 1990
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.320060607
Subject(s) - peroxisome , biochemistry , methylamine , biology , amine oxidase , d amino acid oxidase , cytosol , oxidase test , alanine , ethylamine , amino acid , mutant , enzyme , urate oxidase , chemistry , gene , organic chemistry
We have studied growth of two peroxisome‐deficient mutant strains of Hansenula polymorpha on glucose in the presence of different organic nitrogen sources (methylamine, ethylamine and D ‐alanine), the metabolism of which is mediated by peroxisome‐borne oxidases in wild‐type (WT) cells. Both strains grew well on each of these substrates with growth rates comparable to WT cells. Growth on both methylamine and ethylamine was associated with enhanced levels of catalase and amine oxidase in the cells; in D ‐alanine‐grown cells D ‐amino acid oxidase activity and increased. In WT cells of H ‐ polymorpha the activities of these enzymes were confined to the peroxisomal matrix; however, in both peroxisome‐deficient strains their activities were localized in the cytosol. Electron microscopy indicated that, dependent on the stage of growth, the enzymes may form large protein aggregates. The molecular masses of both amine oxidase and D ‐amino acid oxidase in the mutant strains were identical to their respective counterparts in WT cells, indicating that both proteins were correctly assembled and active in the cytosol.