Two step purification of human and murine leukotriene C4 synthase.

Leukotriene (LT) C4 synthase catalyzes the conjugation of LTA4 with reduced glutathione (GSH) to form LTC4. This enzyme was purified to homogeneity from Kirsten Sarcoma transformed murine mast cells and from the human monocytic cell line THP-1 by two steps: a microsomal extract was partially purified by affinity chromatography on S-hexyl GSH agarose. LTC4 synthase was separated from other GSH-binding proteins by preparative gel electrophoresis under non denaturing conditions. The proteins obtained from human and murine cells showed a single band on a SDS gel with a molecular mass of 14 to 17 kDa, depending on the gel system. N-terminal sequencing revealed high homology between the LTC4 synthases of both species.