Human proprotein convertase subtilisin/kexin type 9 (PCSK9), also known as FH3, HCHOLA3, and PC9, GenBank Accession No. NM_174936, a.a. 31-692(end), with C-terminal His and Avi tags, MW=73.8 kDa (calculated), expressed in an HEK293 cell expression system and enzymatically biotinylated using Avitag™ technology.