This proposal focuses on the enzymatic synthesis of methyl chloride. Methyl chloride transferase, an enzyme which has been recently discovered in Dr. Hager's laboratory, catalyzes the synthesis of methyl chloride from S-adenosylmethionine and chloride ion. Methyl chloride is the most abundant halohydrocarbon in the upper atmosphere and thus becomes a potential candidate for destruction of the ozone layer. The annual global emission rate of methyl chloride from biological sources is estimated to be 5x106 tons. However, there is scientific disagreement concerning the role of naturally occurring halometabolites and man-made chloro- fluoro hydrocarbons (CFCs) in terms of ozone destruction. %%% Methyl chloride transferase in marine algae and halophytic plants may be a mechanism for the injection of massive amounts of methyl chloride into the atmosphere. For example, ice plant grows abundantly on a world-wide basis in temperate coastal regions, thus can be a major contributor to atmospheric methyl chloride. The enzyme may also play a role in salt tolerance of plants. Transformation of soy bean with the gene for the enzyme may lead to the development of salt tolerant plants.
