Figure 5.

a) Routes to in vitro carboxyethylation. Synthesis of cxSAE from SAH and BPA, or enzymatic production of cxSAE using hMAT and CmoA, followed by subsequent CNMT‐catalysed carboxyethylation of THIQ 4. The table insert shows C18 HPLC conversions of THIQ 4 to (R)‐4 c when assayed with WT, Y81R, and Y81K CNMT enzymes and synthetic cxSAE generated from (±)‐, (S)‐, or (R)‐BPA. Assays were done in triplicate and standard errors calculated. b) Independent chiral HPLC assay analysis of carboxyethylated heliamine products from CNMT Y81K and (±)‐, (S)‐, or (R)‐BPA‐derived synthetic cxSAE.