Bromoperoxidase biosynthesis

As noted previously, bromoperoxidase (BPO) is a ubiquitous enzyme that bromi-nates a wide variety of organic substrates (1). Both heme and vanadium BPOs are known and these enzymes are probably the main actor in the biosynthesis of the myriad marine organobromine metabolites (2240-2242, 2329). 

Butler A, Carter-Franklin JN (2004) The Role of Vanadium Bromoperoxidase in the Biosynthesis of Halogenated Marine Natural Products. Nat Prod Rep 21 180... 

Carter-Franklin JN, Butler A (2004) Vanadium Bromoperoxidase-Catalyzed Biosynthesis of Halogenated Marine Natural Products. J Am Chem Soc 126 15060... 

Two vanadium bromoperoxidases that differ in carbohydrate content [26,33] have been isolated from A. nodosum. The most abundant bromoperoxidase, V-BrPO-I, was found in the thallus, and the other bromoperoxidase, V-BrPO-II, was reported to be present on the thallus surface [26], A previous report also concluded that V-BrPO is present in two different locations of A. nodosum, one in the cell walls of the transitional region between the cortex and medulla of the thallus and the other in the cell wall of the thallus surface [34], More recent experiments demonstrate that vanadium-dependent bromoperoxidase activity is present in both the cortical and surface protoplasts of M. pyrifera [35], L. saccharina, and L. digitata [36], The biosynthesis of V-BrPO in the protoplasts of L. saccharina has been shown using [35S]-methionine [36], The vanadium bromoperoxidases are all acidic proteins [26] with very similar amino acid compositions [37], V-BrPO (A. nodosum) has been crystallized, although refined structural data have not been reported yet [38], A different isolation procedure, based primarily on a two-phase extraction system, has been described [39,40], This procedure works well for certain types of algae (e.g., Laminaria) but not for the isolation of V-BrPO from A. nodosum, the principal source of V-BrPO for the mechanistic studies. 

Butler, A., Carter-Franklin, J. N. (2004). The role of vanadium bromoperoxidase in the biosynthesis of halogenated marine natural products. Natural Product Reports, 21, 180—188. 

In recent years, the enzymes responsible for the introduction of halogen in biological systems have been identified. One group of vanadium bromoperoxidases is found in marine algae [69-71]. 7-Chlorination of tryptophan is involved in the biosynthesis of materials such as pyrrolnitrin and rebeccamycin. The enzyme is a flavin-dependent monooxygenase that generates hypochlorite ion. The structure of the enzyme is such that the OCl ion is conducted to the indole binding site over a distance of about 10 A [72, 73]. 

The biosynthesis of long-chain acids with even numbers of carbon atoms having been demonstrated (see above), there is every reason to suppose that the introduction of bromine takes place in the final stage, from the corresponding acid by the action of a bromoperoxidase, and it is reasonable to suppose that the same is true for adds with odd numbers of carbon (Lam et al, 1989). The same mechanism applies to both sets of acids by elongation, desaturation and halogenation, from palmitic acid for even acids and pentadecanoic acid for odd acids, as summarized in Figiue 19.13 (Lam et al., 1989 Carballeira, 1997 Dembitsky and Srebnik, 2002). 

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