Biosynthetic origin

Chemists and biochemists And it convenient to divide the principal organic substances present m cells into four mam groups carbohydrates proteins nucleic acids and lipids Structural differences separate carbo hydrates from proteins and both of these are structurally distinct from nucleic acids Lipids on the other hand are characterized by a physical property their solubility m nonpolar solvents rather than by their structure In this chapter we have examined lipid molecules that share a common biosynthetic origin m that all their carbons are derived from acetic acid (acetate) The form m which acetate occurs m many of these processes is a thioester called acetyl coenzyme A... 

The biosynthetic origin of monobactams has been elucidated by fermentation experiments using radioactively labeled amino acids (qv). The... 

In spite of the number of different structural types, lipids shar e a common biosynthetic origin in that they are ultimately derived from glucose. During one stage of carbohydrate metabolism, called glycolysis, glucose is converted to lactic acid. Pyruvic acid is an intermediate. 

Isotope incoiporation experiments have demonstrated the essential conectness of the scheme presented in this and preceding sections for teipene biosynthesis. Considerable effort has been expended toward its detailed elaboration because of the common biosynthetic origin of terpenes and another class of acetate-derived natural products, the steroids. 

Figure 11.3 Biosynthetic origin of the O-methyl and carbamoyl groups of mitomycin C.

Figure 23-5. The three groups of eicosanoids and their biosynthetic origins. (PG, prostaglandin PGI, prostacyclin TX, thromboxane LT, leukotriene LX, lipoxin , cyclooxygenase pathway , lipoxygenase pathway.) The subscript denotes the total number of double bonds in the molecule and the series to which the compound...

The tetrodotoxins (TTXs) and saxitoxins (STXs) have in common the ability to block sodium channels of excitable membranes (1—5), Saxitoxin and tetrodotoxin are some of the most potent non-proteinaceous neurotoxins known and are responsible for significant human morbidity and mortality (6, 7). Although for many years the biosynthetic origin(s) of TTXs and STXs has not been identified, recent evidence indicates that bacteria may be a source. 

Hamilton JTG, CD Murphy, MR Amin, D O Hagan, DB Harper (1998) Exploring the biosynthetic origin of fluoroacetate and 4-fluorothreonine in Streptomyces cattleya. J Chem Soc Perkin Trans 1 759-767. 

Carotenoids are also fonnd in photosynthetic bacteria and in some fimgi [16]. Snch componnds often have qnite nniqne stmctnral featnres reflecting their biosynthetic origin. Carotenoids fonnd in insects and animals are the resnlt of their retention from materials making np the diet of the organism, althongh the componnds may have snffered minor modifications to allow of their ntilization within the organism [17]. It shonld be noted that carotenoids in marine animals are almost always fonnd as protein complexes, and it is not possible to separate these by thin-layer methods withont prior treatment to remove or denatnre the protein. 

Hojati, Z., Milne, C., Harvey B. et al. (2002) Structure, biosynthetic origin, and engineered biosynthesis of calcium-dependent antibiotics from Streptomyces coelicolor. Chemistry Biology, 9, 1175. 

Cane, D.E., Liang, T.C., Kaplan, L.K. etal. (1983) Biosynthetic origin of the carbon skeleton and oxygen atoms of the avermectins. Journal of the American Chemical Society, 105, 4110-4112. 

The variation of the chemical structures in both Type I and Type II compounds results from differences in both biosynthetic enzyme systems and their starting material. This topic, however, has been judiciously described in the chapter by R. Jurenka. While the grouping employed in this chapter is based on biosynthetic origin, some chemicals were involuntarily classified considering their functional groups more sizably than the origin. Incidentally, taxonomic information is important for insect pheromone research. In this chapter, the family name (with the common suffix -idae) is associated with the species name. For those species whose family name is not listed in Figs. 1 and 2, the superfamily name (with the common suffix -oidea) is associated. The subfamily name (with the common suffix -inae) is also described for the species in Tor-tricidae, Pyralidae, and Noctuidae. 

The repertoire of chemicals that can be used for communication is limited by the biosynthetic ability of the insect. Compared to other insect orders, pheromone biosynthesis in Hymenoptera has received little study [191]. However, the biosynthetic origins of chemically diverse hymenopteran semiochemicals likely include aromatic, fatty acid, and terpenoid pathways as well as simple modifications of host-derived precursors. Notable recent studies include the biosynthesis of the fatty acid components (2 )-9-oxodec-2-enoic acid 52 and (2 )-9-hydroxydec-2-enoic acid of the honeybee queen mandibular pheromone from octadecanoic acid [192,193], and the aliphatic alcohol and ester... 

The biosynthetic origin of the depolymerization-resistant core of cutin (cutan) remains to be established. The early observation that linoleic acid and linolenic acid were preferentially incorporated into the non-depolymerizable core of cutin in apple skin slices suggested that the ether-linked or C-C-linked core might arise preferentially from the czs-l,4-pentadiene system [31]. The insoluble residue, that contained the label from the incorporated polyunsaturated C18 acids, released the label upon treatment with HI, supporting the notion that some of those aliphatic chains were held together by ether bonds. More recently,... 

Scheme 11.2 Potential biosynthetic origin of pseudodimeric complanadines...

Marine organisms frequently contain a complex mixture of sterols. The biosynthetic origin of these compounds is complicated by the fact that there are four possible sources. The sources by which marine invertebrates may obtain sterols, first described by Goad [3], are (1) de novo biosynthesis, (2) assimilation from diet, (3) modification of dietary sterols and (4) assimilation of symbiont-produced sterols or sterol precursors. In any examination of the biosynthetic origin(s) of sterols one must consider all of these factors needless to say, a complex picture is emerging. 

The studies on the biosynthetic origin of secondary metabolites in marine molluscs are reviewed. Although the majority of natural products found in marine molluscs appears to have a dietary origin, de novo biosynthetic ability towards particular classes of compounds has been demonstrated. Marine molluscs are also able to modify metabolites sequestered from their specific prey. 

Structural similarities between the monomeric units of aplydilactone (144) and the red algal metabolites constanolactone A (145) and B (146), suggest an analogous biosynthetic origin. Dehydration of two m3 unsaturated eonstanolac-tone-type units could result in the formation of the unsymmetrical dimer (Scheme 11). Since sea hares are known to feed extensively on red algae and sequester natural products from this source, it remains possible that aplydilactone (144) derives, at least in part, from a dietary source. 

Figure 5.1. The basic C6-C3-C6 flavonoid skeleton (upper panel) and typical flavonoid subgroups (lower panel). The biosynthetic origins of carbon atoms and standard numbering are also illustrated in the upper panel.

Chemical structure can often be used by itself to recognize a secondary metabolite because of their common biosynthetic origin Terpenes and polyketides, for... 

Fig. 1.2 Biosynthetic origin of the major classes of natural products...

The second largest class of compounds reported from macroalgae is the polyketides, which comprise approximately a quarter of known algal compounds (Blunt et al. 2007). Polyketides are polymers of acetate (C2) and occasionally propionate (C3) and are very similar to fatty acids in their biosynthetic origin. Polyketides can be found in plants, animals, bacteria, and fungi. With a range of activities as broad as their structures, the polyketides are a diverse family of natural products classified based upon the polyketide synthases (PKSs) responsible for their biosynthesis, primarily type I and type II. 

The majority of natural products from tropical macroalgae are terpenoids (mainly sesqui- and diterpenoids), followed by acetogenins (acetate-derived compounds), and metabolites of mixed biosynthetic origin (such as meroditerpenes), frequently composed of terpenoid and aromatic portions (Blunt et al. 2007 and previous reviews see Chap. 1). 

FIGURE 11. Biosynthetic origin of fungichromic (54) and structure of oleate analog (56). Reproduced by permission of Japan Antibiotics Research Association from Reference 39... 

In the last ten years, research in the field of insect defensive chemistry has made remarkable breakthroughs which would not have been possible without the advances in separation techniques, structure determination methods, and synthetic methodology. The structures of structurally complex compounds can now be determined on less than 1 mg of material, as exemplified by the hexa- and heptacyclic coccinellid alkaloids. Moreover, in-depth investigations on the biosynthetic origins of some of the defensive compounds are now made possible and will surely bring interesting data in the future. 

Naturally air-fused DKPs are thermodynamically more stable, compared with their trawr-fused counterparts. This seems logical considering their biosynthetic origin, usually from two proteinogenic L-a-amino acids. Some other cis- and rntwr-functional DKPs are derived from nonproteinogenic D-a-amino acids. Naturally... 

---