19.4 ± 1.3 min -1 and 24.6 ± 1.9 mM, respectively, and kcat/KM was calculated to be 0.79 ± 0.1 mM - 1 min -1 , which is approximately one order of magnitude higher than the reported value for the native substrate (Table ). Preliminary docking studies suggest that D-Nip exhibits a different binding mode than ectoine in the active site, specifically by relying on the polar interactions between the carboxylate motif and Gln127, Arg129 and Arg280 (Figure ). With the aforementioned building blocks at hand, routine Boc protection completed the synthesis of five key piperidines 14-18, which form the basis of subsequent synthetic explorations. While four out of these five building blocks are commercially available, their purchase costs are prohibitively expensive ($773-$1737/g).