SYNTHESIS OF BROMINATED HEPTANONES AND BROMOFORM BY A BROMOPEROXIDASE OF MARINE ORIGIN

The presence of naturally occurring volatile halohydrocarbons in marine organisms, seawater and the upper atmosphere has prompted a search for their biosynthetic origin. An earlier report documented the preparation of an enzyme extract from a marine algae which catalyzed the formation of dibromomethane, tribromomethane and 1-bromopentane from 3-oxooctanoic acid. This report did not establish a pathway nor did it examine potential intermediates involved in the synthesis of the halometabilities (Theiler, R., Cook, J., Hager, L., et Siuda, J.). An extract of the green marine algae, Penicillus capitatus, which contains a potent bromoperoxidase activity, is capable of catalyzing the incorporation of bromide ion into organic combination in the presence of 3-oxooctanoic acid. By use of gas chromatography and mass spectroscopy, tribromomethane, 1-bromo-2-heptanone, 1,1-dibromo-2-heptanone and 1,1,1-tribromo-2-heptanone as products of this reaction were identified. The properties of the enzymatically synthesized products were compared to authentic compounds and found to be identical. The mono- and dibromoheptanones can be utilized as precursors for the enzymatic formation of tribromoheptanone but the final hydrolysis of the tribromoheptanone to bromoform appears to be a nonenzymatic reaction with the P. capitatus extracts.