Incorporation of [14C]radiolabel into acceptor substrates containing various Hyp motifs. [AO]7, [AO]14, and dd[AO]51 contain 7, 14, and 51 [AO] units, respectively. A chemically synthesized ExtP and tomato dExtP2 contain repetitive SO4 units. [AP]7 contains seven [AP] units. Enzyme reactions were done in triplicate, and mean values are presented.