The minimal catalytic domain of 1,3/4 fucosyltransferases (FucTs) from Helicobacter pylori strain NCTC11639 and UA948 was mapped by N-terminal and C-terminal truncations. Only the C-terminus could be truncated without significant loss of activity. 11639FucT and UA948FucT contain 10 and 8 heptad repeats respectively, which connect the catalytic domain with the C-terminal putative amphipathic -helices. Deletion of all heptad repeats almost completely abolished enzyme activity, nevertheless, with only one heptad repeat 11639FucT is fully active while UA948FucT is partially active. Removal of the two putative amphipathic -helices dramatically increased protein expression and solubility, enabling purification with yields of milligrams per liter. Steady-state kinetic analysis of the purified FucTs showed that 11639FucT possessed slightly tighter binding affinity for both Type II acceptor and GDP-fucose donor than UA948FucT, and its k_cat of 2.3 s^-1 was double that of UA948FucT, which had a k_cat value of 1.1 s^-1 for both Type II and Type I acceptors. UA948FucT strongly favors Type II over Type I acceptor with a 20-fold difference in acceptor Km. Sixteen modified Type I- and Type II-series acceptors were employed to map the molecular determinants of acceptors required for recognition by H. pylori 1,3/4 FucTs. Deoxygenation at 6-C of the galactose in Type II acceptor caused a 5000-fold decrease in 1,3 activity whereas in Type I acceptor this completely abolished 1,4 activity, indicating that this hydroxyl group is a key polar group.