MoAb 97A6 detects 130- and 150-kd proteins that correspond to E-NPP3.

(A) Lysates of KU-812 cells were affinity purified on a 97A6-Sepharose column and separated on 7.5% SDS-PAGE. The silver-stained proteins had a molecular mass of 130 kd and 150 kd, respectively. (B) The sequences of E-NPP1 (PC-1) and E-NPP3 (PDNP3) are aligned with tryptic HPLC-purified 97A6 peptides derived from the cut bands shown in panel A. The sequence of the digested peptides (identical peptides from both bands) shows a complete match with amino acids 393 to 405 of E-NPP3. Although the primary structures of E-NPP family proteins share a significant similarity, the sequence of this region differs considerably between E-NPP1 and E-NPP3.