Most species of Staphylococcus aureus produce a protein known simply as protein A. This protein consists of a single polypeptide chain of molecular weight 42 kDa. Protein A binds the Fc region (the constant region) of immunoglobulin G (IgG; Chapter 13) obtained from human and many other mammalian species with high specificity and affinity. Immobilization of protein A on chro-matography beads provides a powerful affinity system that may be used to purify IgG. There is, however, a considerable variation in the binding affinity of protein A for various IgG subclasses obtained from different mammalian sources. In some cases another protein, protein G, may be used instead of protein A. Most immunoglobulin molecules that bind to immobilized protein A do so under alkaline conditions, and may subsequently be eluted at acidic pH values.
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All you need is a proper diet of fresh fruits and vegetables and get plenty of exercise and you'll be fine. Ever heard those words from your doctor? If that's all heshe recommends then you're missing out an important ingredient for health that he's not telling you. Fact is that you can adhere to the strictest diet, watch everything you eat and get the exercise of amarathon runner and still come down with diabetic complications. Diet, exercise and standard drug treatments simply aren't enough to help keep your diabetes under control.