Some basic things to expect include a lot-specific Certificate of Analysis that will detail the identity of the protein and analytical testing that has been done to ensure the material is meeting specifications. A Certificate of Origin may be obtained that provides traceability of the materials used in manufacturing of the protein. This would be key document for those wanting to establish they are working with animal-free raw materials. Drug Master Files (DMFs) may also be submitted to regulatory authorities by the supplier. DMFs provide details about manufacturing process and can be referenced during filing. They also provide a mechanism for submitting proprietary information. A supplier should be very open to audits of their facilities where you can review batch records that provide critical information about lot-to-lot consistency. Lastly, look for someone with experience. Chances are they’ve run across most questions, and they can be an asset as you move through the process.