Hi All,

Invitrogen tech services told me categorically yesterday by phone that Freestyle F-17 media (A13835) contains NO biotin.

This seems to directly contradict what IBA and other groups have measured in this media. We should really pressure Invitrogen to be more open about SINGLE components of their media formulations. If they give us the concentration of one component we are not exactly going to be able to reverse engineer a complex media and in this instance it would help us all dramatically with our purification workflows.

We actually used IEX  (SPXL 5ml FF column at pH6 with MES) for this protein because we have previous data and we know how it behaves but this is not going to be a universal strategy for OneStrep tagged proteins from this media.

Thanks again everyone for your rapid responses and suggestions-Viva P4EU!!!

Nick

Hi All,

Invitrogen tech services told me categorically yesterday by phone that Freestyle F-17 media (A13835) contains NO biotin.

This seems to directly contradict what IBA and other groups have measured in this media. We should really pressure Invitrogen to be more open about SINGLE components of their media formulations. If they give us the concentration of one component we are not exactly going to be able to reverse engineer a complex media and in this instance it would help us all dramatically with our purification workflows.

We actually used IEX  (SPXL 5ml FF column at pH6 with MES) for this protein because we have previous data and we know how it behaves but this is not going to be a universal strategy for OneStrep tagged proteins from this media.

Thanks again everyone for your rapid responses and suggestions-Viva P4EU!!!

Nick

Well everyone EXCEPT Life/Invitrogen knows that their F-17 media contains biotin. The avidin that we have had to add this time (Q/S IEX unfortunately has not worked with the current protein) puts the biotin concentration exactly in line with the estimates from IBA and Joop (thanks!).

This is not the first time that their inadequate technical support has cost us in terms of experiments and reagents. I am switching to a supplier that will answer my questions about media without a CDA to find the concnetration of one component essential for downstream processing!

Hi All,

Just a quick update on this-I have a bulk (500mg)source of biotin that works well for this application with a pricing of approx. €1/mg. For the F-17 that would work out at about €60-70/litre if the options of cross-flow filtration and/or IEX are  not available to you for a particular protein.

Contact me for supplier details if you are interested.