FIG. 4.

(A) SDS-10% PAGE shows a homogeneous enzyme preparation after the final purification step. Lane 1, molecular weight marker; lane 2, purifed erythrose reductase. (B) In vitro activity staining assay demonstrating that fumarate specifically inhibits the activity of erythrose reductase. Lane 1 contains no TCA cycle intermediates. Lanes 2 to 7 contain TCA cycle intermediates as follows: lane 2, 10 mM citrate; lane 3, 10 mM α-ketoglutarate; lane 4, 10 mM succinate; lane 5, 10 mM malate; lane 6, 10 mM oxalacetate; and lane 7, 10 mM fumarate. ER, erythrose reductase.