B O-glucosyltransferase activity towards five different single EGF repeats from mouse Notch1. Wild-type POGLUT1 shows higher activity toward all EGF repeats tested than POGLUT1D233E. The Y-axis shows the normalized activity relative to wild-type POGLUT1. EGF repeats were at 10 μM. Values indicate mean ± SEM from three independent assays. 