Mouse secreted CTLA4, with C-terminal Avi-Tag fused at the C-terminus with the Fc portion of human IgG1 and biotin labeled, also known as Cytotoxic T-lymphocyte-associated protein 4 and CD152. GenBank Accession No. NM_009843, a.a. 36-161 expressed in a HEK293 cell expression system. The protein is enzymatically biotinylated using AviTag™ technology. MW = 42 kDa. This protein runs at a higher MW by SDS-PAGE due to glycosylation.