Yeast strains and modified albumins
AssigneeDelta Biotechnology Limited
InventorsSean Martin Kerry-Williams, Sarah Catherine Gilbert
Life of this patent
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Abstract
Albumin, for example human albumin, is expressed and secreted in yeast which has been mutated to lack the yeast aspartyl protease 3 (Yap3p) or its equivalent, thereby reducing the production of a 45 kD albumin fragment. A further reduction is achieved by additionally deleting the Kex2p function. Alternatively, a modified albumin is prepared which is not susceptible to Yap3p cleavage, for example human albumin which is R410A, K413Q and K414Q.
Claims27
A process for preparing albumin comprising:
- genetically modifying yeast cells having a reduced level of yeast aspartyl protease 3 proteolytic activity of at most 50% as compared to the corresponding activity level of naturally-occurring yeast cells of the same kind, to produce and secrete albumin, and culturing said yeast cells in a culture medium such that albumin is secreted into said culture medium.
A culture of yeast cells having a reduced level of yeast aspartyl protease 3 proteolytic activity of at most 50% as compared to the corresponding activity level of naturally-occurring yeast cells of the same kind, containing a polynucleotide sequence encoding an albumin and a second polynucleotide sequence encoding a secretion signal causing albumin expressed from the first polynucleotide sequence to be secreted from the yeast.
A modified albumin, which when expressed and secreted in yeast is non-susceptible to cleavage with yeast aspartyl protease 3 (YAP3p).
Dependencies are inferred from the claim text.