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Is the presence of free biotin in the medium (in case of proteins secreted to the medium) a problem (eukaryotic expression)?

April 26, 2017Biotin Case eukaryotic expression Free medium presence problem Proteins secreted

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Is the presence of free biotin in the medium (in case of proteins secreted to the medium) a problem (eukaryotic expression)?

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Free Biotin inactivates Strep-Tactin resins (biotin capacity ≅ 350 nmol/ml sedimented resin) and has to be removed or masked prior to affinity chromatography. This is mostly relevant when cell culture supernatant, containing secreted recombinant protein, is directly subjected to Strep-Tactin affinity chromatography because some media for insect cells or mammalian cells contain significant amounts of biotin (see table below). The simplest way to get rid of the biotin problem for purification of secreted eukaryotic proteins is irreversible masking by the addition of avidin [Cat.-no.: 2-0204-050] using 120 mg avidin per mg contaminating biotin. This procedure is recommendable at high expression levels.