The invention relates to purification of an intact, non-degraded macromolecule from a biological mixture comprising the macromolecule in the presence of its lytic enzyme. The method comprises providing the biological mixture as a heterogeneous mixture comprising the lytic enzyme, at least partially, in soluble form and the macromolecule, at least partially, in non-soluble form; batch-wise contacting the heterogeneous mixture with an immobilized inhibitor of the lytic enzyme; increasing the solubility of the macromolecule in the mixture; and removing the immobilized inhibitor from the mixture.