A soluble chimeric form of pBORFF3–4 has core 2, core 4, and I branching activities. Soluble chimeric forms of pBORFF3–4 (filled bars) and h-C2GnT-M (hatched bars) were assayed for C2GnT, C4GnT, dIGnT, and cIGnT activities as described in Materials and Methods. The results are expressed relative to C2GnT activity, which is defined as 100%. The C2GnT activity was 45.3 pmol/h per ml and 84.0 pmol/h per ml for chimeric pBORFF3–4 and chimeric h-C2GnT-M, respectively. Bars represent standard errors for duplicate measures.