FIG. 3.

Mass spectra of dimethyl esters of E-PI and its putative 3-methyl homolog. (A) E-PI acid standard. (B) E-3-MePI (or a closely related isomer) produced from 3-MeBS, succinyl-CoA, and nitrate by permeabilized cells of Azoarcus sp. strain T (Table 1).