History of 1,3-dichloropropene

In the last century, man has used pesticides to combat crop-destroying pests such as nematodes. Use of 1,3-dichloropropene became prevalent in the 1940s under the name "Telone Soil Fumigant". This toxic pesticide breaks down in the soil, due to microbial metabolism (to a very stable compound (trans-3-chloroacrylate) in soil A recent publication characterized a specific dehalogenase enzyme (3-chloroacrylic acid dehalogenase or CaaD) that breaks down this incredibly stable compound into a common metabolite. This enzyme was discovered in a bacterial species indigenous to soils contaminated with 1,3-dichloropropene, and CaaD shares much in common (both catalytically and kinetically) with key metabolic processes common to all organisms.

 

Importance of Research

CaaD catalyzes an interesting reaction, specifically, the removal of a halogen atom from a vinylic carbon of trans-3-chloroacrylate. Enzymes that catalyze this particular reaction are somewhat rare in nature, so information gained from the study of this enzyme is important both in understanding the biology of the host bacteria, and in understanding the cause of the catalytic and kinetic proficiency. Since the products of the degradation of 1,3-dichloropropene by the bacteria (3-chloroalyll alcohol and trans-3-chloroacrylate) are toxic and can easily permeate ground water supplies (Cohen et. al., 1983), and since CaaD degrades trans-3-chloroacrylate into a harmless metabolite, understanding this enzyme may protect us from consuming contaminated food from pesticide treated crops, and water from pesticide treated areas.