The FOLR1 protein is an important mediator of folate uptake, binding to folate and promoting the delivery of 5-methyltetrahydrofolate into cells. Studies show high affinity at neutral pH. FOLR1 Protein, Human (Biotinylated, HEK293, His-Avi) is the recombinant human-derived FOLR1 protein, expressed by HEK293 , with C-Avi, C-6*His labeled tag.