FGF4 stock solution

Human recombinant fibroblast growth factor-4 (FGF4; Sigma)

0.1% (w/v) BSA fraction V in PBS

To make a 1000x, 25 μg/ml stock solution of FGF4, resuspend lyophilized FGF4 in its vial with 1.0 ml of 0.1% (w/v) bovine serum albumin (BSA) in phosphate-buffered saline (PBS). Mix well, divide into 100-μl aliquots, and freeze at -80°C. Thaw each aliquot as needed and store at 4°C. Do not refreeze.