TABLE 3.

Product yields from assays of permeabilized cells of m-xylene-grown Azoarcus sp. strain T utilizing alternate substrates^a

Substrate added				Product (or respective methyl homolog) (nmol)b			Product labeling
Aromatic compound	Fumarate	Succinyl-CoA	Nitrate	BS	E-PI	Benzoate
Toluene-d8 (340 nmol, total)	+	+	+	190	6	47	Deuterium labeled
BS (150 nmol, total)	−	+	+	98	7	6
o-Xylene-d10 (300 nmol, total)	+	+	+	230	12	NDc	Deuterium labeled
p-Xylene-d10 (360 nmol, total)	+	+	+	110	8	70	Deuterium labeled

^aEach anoxic assay mixture (total volume, 1 ml) contained titanium(III) chloride (200 μM) as a reductant and permeabilized cells (ca. 3 mg of protein). Initial concentrations of other substrates added are given as follows: fumarate, 500 μM; succinyl-CoA, 300 μM; and nitrate, 2 mM. A total of 340 nmol of toluene, 300 nmol of o-xylene, and 360 nmol of p-xylene is equivalent to a liquid concentration of 160, 170, and 170 μM, respectively. Assays were incubated for 1 h. Reaction products were extracted, derivatized to methyl esters, and analyzed by GC/MS. 

^bBS, E-PI, and benzoate were identified by GC/MS by using authentic standards. The 2- and 4-methyl homologs of BS and E-PI were tentatively identified based on mass spectral similarities to authentic standards of BS and E-PI, respectively. Product yields are averages of duplicate assays, except for the p-xylene assay. All of the assays shown in Table 3 were conducted with the same batch of cells. 

^cND, not detected. The detection limit of 2-methylbenzoate was less than 0.4 nmol. 2-Methylbenzoate was detected, but the concentration was too low to quantify.