Protein A from Staphylococcus aureus, Cowan I Strain conjugated with highly purified horseradish peroxidase (RZ > 3.0).

The product is liquid containing 10 mM phosphate, 0.15 M NaCl buffer, pH 7.4, 1% ovalbumin, 40% glycerol, and 0.1% proclin as preservative.