Figure 3.

NMT3 has the capacity to catalyze the triple methylation of PEA to PCho. A, ³¹P-NMR spectra of PEA and PCho standards in HED buffer, pH 8.2. B to D, Time course of PEA methylation reactions catalyzed by protein extracts from yeast cells expressing pYES-DEST52:NMT3 (B), empty vector pYES-DEST52 (C), or pYES-DEST52:NMT1 (D). Shown are ³¹P-NMR spectra recorded 5 min, 17 h, 40 h, and 137 h after the initiation of the reaction through the addition of substrates PEA and S-adenosyl methionine (B). Only the initial and final spectra, recorded at the 5-min and 137-h time points, respectively, are shown in C and D.