Protein Tyrosine phosphorylation was first described in 1979. The development of the Anti-Phosphotyrosine, clone 4G10 in 1989 was a monumental discovery for researchers. 4G10 is the first and best single monoclonal antibody for the detection of tyrosine phosphorylation. It is the most highly cited (75% of related scientific journal articles over the last three years) and validated phosphotyrosine antibody available. It consistently produces high quality, reproducible data, and has been validated by thousands of scientific and medical researchers in virtually every application and tyrosine target over the past 18 years. In addition to its unparalleled characterization and applicability, 4G10 is well known as one of the most sensitive anti-phosphotyrosines. Now Millipore is excited to announce that we have taken the sensitivity for phosphotyrosine detection to the next level. To improve on something that hundreds have tried and none have succeeded, we pooled 4G10 with the next most highly regarded Anti-phosphotyrosine, clone PY20 to make 4G10 Platinum. PY20 itself is a very poor substitute for 4G10, but its additive effect allows for a greater level of detection on more substrates that even 4G10 alone was capable of.