It is rare for recombinant proteins to be the same molecular weight as their natural counterpart. Sequences are either deleted or added as a function of the restriction enzyme sites in the nucleic acid or the expression vector used to produce the proteins. Additionally, there are sometimes oligomers and partial cleavage products. Neither affects the function, but sometimes they will cause confusion. To alleviate doubt, use a monoclonal antibody to demonstrate the protein in a Western blot or ELISA. Please see the specification sheet for each protein for its correct molecular weight.