Catalyzes the formation of 1,2-bis-O-sinapoyl beta-D-glucoside and an unidentified compound 1. 2 1-O-(trans-sinapoyl)-beta-D-glucose = 1,2-di-O-sinapoyl beta-D-glucose + D-glucose A number of isoforms are produced. According to EST sequences. Expressed in seedlings, leaves, flowers and siliques. Decreased levels of 1,2-disinapoyl-glucose due to a partial redundancy with SCPL8 and SCPL13. Belongs to the peptidase S10 family. Was classified as a serine carboxypeptidase-like (SCPL) protein solely on the basis of the overall sequence similarity (PubMed:15908604) but it has been shown that it belongs to a class of enzymes that catalyze acyltransferase reactions (PubMed:17600138).