13C Mims ENDOR for LAM with [13C-methyl]-anSAM, PLP and substrate with simulation spectrum. Spectrum collected at radical peak. Experimental conditions: MF = 34.74 GHz, MW pulse length (π/2) = 50 ns, τ = 400 ns for Mims, and T = 2 K. Simulations (blue) with ENDOR line-widths of 0 and 0.28 MHz; parameters, Aiso = −0.61 MHz, T = 0.21 MHz (distance r = 3.6 Å).