Branched-chain fatty acids are excellent substrates for a bacterial enzyme, suggesting that they might be part of a biologically significant process.

Researchers led by James De Voss at the University of Queensland, Australia, have discovered that branched-chain fatty acids are very likely to be the natural substrates for the enzyme P450_BM3. The enzyme is isolated from the bacterium Bacillus megaterium. P450_BM3 has received significant interest over recent years, said De Voss, but its exact role has remained elusive. 

Straight-chain fatty acids had previously been shown to be good substrates for the enzyme, but these acids form less than 5 per cent of the substrates in vivo - the majority are branched-chain acids. De Voss and his team have shown that these branched-chain acids are oxidised more efficiently, indicating that this reaction might be biologically significant.

P450_BM3 is an unusual member of the cytochrome P450 superfamily of enzymes, said De Voss. P450 enzymes catalyse a wide variety of biologically significant oxidation reactions, such as the excretion of drugs from the human body. De Voss said that P450_BM3 is of interest because it is particularly efficient, and catalyses a rapid turnover of substrates. It also an attractive target for modification and possible applications to synthetic and industrial processes, he said.

This discovery will 'aid in determining the biochemical significance of this important enzyme and the role of other P450s found in Bacillus species,' said De Voss.

David Barden