Enantioselective Dehydrochlorination of delta-Hexachlorocyclohexane and delta-Pentachlorocyclohexene by LinA1 and LinA2 from Sphingobium indicum B90A

delta-Hexachlorocyclohexane (delta-HCH), one of the prevalent isomers of technical HCH, was enantioselectively dehydrochlorinated by the dehydrochlorinases LinA1 and LinA2 from Sphingobium indicum B90A to the very same delta-pentachlorocyclohexene enantiomer. Racemic delta-pentachlorocyclohexene, however, was transformed with opposite enantioselectivities by the two enzymes. A transformation pathway based on an anti-1,2-elimination, followed by a syn-1,4-elimination and a subsequent syn-1,2-elimination is postulated.