Patent ID: 7670821

Claim:
A method for purifying Rhizomucor miehei aspartic protease or Rhizomucor pussilus aspartic protease, comprising: (i) providing an aqueous liquid sample comprising a Rhizomucor miehei aspartic protease or Rhizomucor pussilus aspartic protease, and a separation medium comprising a base matrix and a plurality of attached ligands that are capable of binding to aspartic protease; (ii) contacting the separation medium with the sample under conditions permitting binding of the aspartic protease to the separation medium, wherein said conditions comprise a conductivity of <5 mS·cm −1 ; and (iii) desorbing the Rhizomucor miehei aspartic protease or Rhizomucor pussilus aspartic protease from the separation medium; wherein the base matrix is hydrophilic, the plurality of ligands comprise hydrocarbon groups in which all carbon atoms are sp 3 -hybridised, and each hydrocarbon ligand is bound to the base matrix (a) by directly attaching said hydrocarbon ligand to an oxygen or sulphur heteroatom that is part of the base matrix, or (b) via a spacer that comprises a bivalent functional group other than ether or thioether in which the functional group is attached directly to one of the hydrocarbon ligands.