Range of substrates assessed in this study with the CalO6 substrate SNAC-OSA (4) and CalO6 reaction products P1 and P2 highlighted within the box. B. HPLC chromatogram of a representative CalO6 reactions with 4 at 37 °C for 1 h (i: SAM; ii: 4; iii-v: CalO6 reactions containing 8, 16 and 24 μg of enzyme, respectively). Peaks labeled with S, P1 and P2 are substrate, SNAC-OSA, SNAC-2-methoxy-OSA and SNAC-4-methoxy OSA, respectively and SAH and/or SAM degradation products are denoted by stars (*) C. Sections of the P1 and P2 NOESY spectra (mixing time = 300 ms) where arrows in A indicate key NOE connections.