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Expired Canadian patentCanada

Method of recovering microbially produced recombinant ricin toxin a chain

CA 1308680 C · Owner: Cetus Corporation · Inventors: Ferris, Robert

CIPO record

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Abstract From the Canadian patent

Substantially pure intracellularly produced, soluble, recombinant ricin toxin A (RTA) is recovered from transformed cells by disrupting the cell membrane, removing insoluble cell membrane materials from the disruptate, adjusting the pH of the cell membrane material-free solution to 6 to 6.5 and the conductivity to 1.25 to 1.75 millisiemens, passing the adjusted solution through a bed of SPcellulose cation exchanger, and eluting the substantially pure RTA from the bed.

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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.

Why it's free to use

  • Granted October 13, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended October 13, 2009.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledFebruary 4, 1987
GrantedOctober 13, 1992
Term endedOctober 13, 2009
Patent numberCA 1308680 C
Classification (IPC)C07K14/41

Timeline

Timeline From CIPO dates

19881991199419972000200320062009Application filedFeb 4, 1987Patent grantedOct 13, 1992Term endedOct 13, 2009

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.