EPO it is not an invention it exists in us,
it is essential to the manufacture of our
red globules. People diverted his use to
improve his sports performances.
Indeed, the EPO injection increase red
globules production. It means that our
muscles will be more oxygenated
during the effort and will be therefore
more effective.

By definition a recombinant protein
should be the clone of the natural
protein manufactured. The only
difference between the 2 proteins is
the host who manufactures it. In a
case it is human who manufactures
his own protein and therefore it is a natural protein. In the other case it is a living being different than human who is assigned to manufacture the human protein. We says in this case that the protein is recombinant. Logically these 2 proteins should be the same. It is the fact, but not for EPO.

Evidently human epo is manufactured in human and what about recombinant EPO ? And it is manufactured while using CHO cells that are ovarian hamster cells. you are going to tell me but how hamster cells are abble to manufacture human recombinant EPO ? It is simple, proteins are coded by genes, it is sufficient to isolate the sequence in nucleic acids coding for the human EPO, and to integrate it to the host cells (in the case of the EPO it is the CHO cells of hamster). This cell manufactures some proteins for its own survival and synthesize in the stride human EPO (since we transferred him the sequence coding for the human EPO). It is then logical that the EPO manufactured by human and the EPO manufactured by the host has the same sequence in amino acids. However EPO is a glycoprotein. I mean that sugars is implanted on some amino acids of the proteins by enzymes. (see the picture below)

Human epo contains only mono, di and tri oligosaccharide acids but doesn't contain any structures tetra oligosaccharide acids that is only present on recombinant EPO (rhEPO). on the other hand some structures are not synthesized by the CHO cells because they don't possess the adequat enzymes that is present in human, notably the sialyl a 2-6 transférase, the N-acétyl glucosamine transferase and the 1-3/4 fructosyl transferase

So, the profile in sugars of the human EPO and the recombianat EPO are different.

These differences permit to know if a sportsman is doped. How? While comparing the isoelectric point of the two proteins. Indeed, the natural EPO stops its migration to a pH between 3,92 and 4,42 while the recombinant EPO stops its migration to a pH between 4,42 and 5,11.

In other words we ask to Mr.X to make a small pee and we make an analysis of the isoelectric point in this manner : the sample of urine to analyze is installed on an electric plate covered of a gel more acidic at one extremity and more basic to the other. While applying an electric current to the plate, natural EPO and recombinant EPO advance in the gel, driven by their charges. But they don't evolve at the same speed and not in the same sense on the plate. The natural epo stops its migration to a pH between 3,92 and 4,42 while the recombinant EPO is stopped to a pH between 4,42 and 5,11 (see picture above). With this method, we can identify the natural EPO and the recombinant EPO