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Our identity testing is performed by SDS-PAGE for molecular weight and analysis by densitometry to verify purity. We also use mass spectrometry and N-terminal sequencing of the first 10 amino acids. Endotoxin, bioburden, host cell protein, and mycoplasma testing is also done. Additional testing may be performed depending upon the protein expressed and the cell line utilized to manufacture the product. Requests for additional analytical testing are regularly addressed for customers.