FIG. 5.

Kinetics of 3-MeBS formation from fumarate (500 μM) and either unlabeled m-xylene (300 nmol, total) (▵) or m-xylene-d₆ (300 nmol, total) (▴) by permeabilized cells of Azoarcus sp. strain T (ca. 0.8 mg of protein). Assays were conducted in parallel. The data points at 5, 10, and 15 min are from duplicate assays. Fitting of the data by linear regression yielded a specific rate of 3-MeBS formation of 3 nmol · min⁻¹ · (mg of protein)⁻¹ (r² = 0.971) from unlabeled m-xylene and 1 nmol · min⁻¹ · (mg of protein)⁻¹ (r² = 0.959) from m-xylene-d₆. The yield of unlabeled 3-MeBS was corrected to account for carryover from growth of the cells on m-xylene. The amount of carryover was estimated to be ca. 0.5 nmol of 3-MeBS, which was the amount of unlabeled 3-MeBS observed in kinetic assays amended with deuterium-labeled m-xylene only.