Tyrphostin A1 is part of the class of low molecular weight protein tyrosine kinase inhibitors. While a majority of Tyrphostins are tyrosine kinase blockers and are being researched as potential drugs for leukemias, cancers, psoriasis, as well as other proliferative conditions, Tyrphostin A1 is the inactive form. Tyrphostin A1 has usually been chosen as the negative control for Tyrphostin A23 and other Tyrphostin derivatives. [Santa Cruz Biotechnology].