What Staph aureus strain is the Protein A reference standard from?
We originally used protein A purified from strain A676. We believe that it is good that the customer has the possibility to obtain the reference material independently of IMMUNSYSTEM AB. We thus use recombinant protein A from GE Healthcare (Uppsala, Sweden) as a reference in the kit. Originally, we chose GE Healthcare (Pharmacia at that time) as they were the first company to market protein A and they had the patent for purifying protein A on human IgG sepharose. The patent has now expired. They are also one of the largest producers of recombinant protein A. GE Healthcare purifies their protein A on Human IgG sepharose.
