– Major envelope protein that plays a role in the biogenesis of the viral double membrane and in egress of virus from the host cell. Produces the wrapped form of virus that is required for cell-to-cell spread. Acts as a lipase with broad specificity including phospholipase C, phospholipase A, and triacylglycerol lipase activities. Vaccinia virus (strain Western Reserve) OPG057 Protein (His & Myc) is expressed in E. coli expression system with N-10xHis and C-Myc tag. The predicted molecular weight is 49.2 kDa and the accession number is P04021.