Stabilization of peroxidase conjugates in solution

A peroxidase conjugate composition consisting essentially of (i) said peroxidase which is conjugated to a member selected from the group consisting of an antibody, a lectin, protein A, protein G, streptavidin, and avidin, and (ii) a polymer selected from the group consisting of:

• up to about 2 % weight per volume (w/v) of polyethylene oxide having a molecular weight of about 100,000 to about 600,000;
• about 2% to about 10% weight per volume (w/v) of polyethylene oxide having a molecular weight of about 100,000;
• from about 2% to about 5% weight per volume (w/v) of polyethylene oxide having a molecular weight of about 300,000;
• about 2% weight per volume (w/v) of polyethylene oxide having a molecular weight of about 600,000;
• about 2% weight per volume (w/v) of polyethylene oxide having a molecular weight of about 900,000;
• about 1% weight per volume of polyethylene oxide having a molecular weight of about 5,000,000;
• from about 0.5 to about 10% weight per volume (w/v) of polyvinyl alcohol of molecular weight of up to about 10,000;
• and from about 1 to about 5% weight per volume (w/v) of polyvinyl alcohol of molecular weight of about 124,000 to 186,000;
• wherein said amounts of said selected polymers are sufficient to stabilize the enzymatic activity of said peroxidase in said peroxidase conjugate.