Camphor metabolic pathways

The understanding of the degradation of natural products such as camphor has been greatly enhanced by understanding the catalytic cycle of the cytochrome P-450 enzyme P-450cam in structural detail.3,4 These enzymes catalyze the addition of 02 to nonactivated hydrocarbons at room temperatures and pressures - a reaction that requires high temperature to proceed in the absence of a catalyst. O-Methyltransferases are central to the secondary metabolic pathway of phenylpropanoid biosynthesis. The structural basis of the diverse substrate specificities of such enzymes has been studied by solving the crystal structures of chalcone O-methyltransferase and isoflavone O-methyltransferase complexed with the reaction products.5 Structures of these and other enzymes are obviously important for the development of biomimetic and thus environmentally more friendly approaches to natural product synthesis. 

The metabolic pathway of (+)-camphor (37) by microorganisms is shown in Figure 19.189. (+)-Camphor (37) is metabolized to 3-hydroxy- (243), 5-hydrot - (235), 6-hydroxy (228), and 9-hydroxycamphor (225) and 1,2-campholide (237). 6-Hydroxycamphor (228) is degradatively metabolized to 6-oxocamphor (229) and 4-carboxymethyl-2,3,3-trimethylcyclopentanone (230), 4-carboxymethyl-3,5,5-trimethyltetrahydro-2-pyrone (231), isohydroxycamphoric acid (232), isoketocamphoric acid (233), and 3,4,4-trimethyl-5-oxo-tran5 -2-hexenoic acid (234), whereas... 

Metabolic pathways of bomeol (36), camphor (37), phellandral (64), linalool (206), and p-men-thane (252) are summarized in Figure 14.202. Bomeol (36) is formed from P-pinene (1), a-pinene... 

CYPs have a role in bacteria to enable growth on carbon sources in the environment, such as on camphor by P. putida containing CYPlOl, or to undertake secondary metabolism as part of the biochemical warfare between organisms. Many CYPs are found in the pathways synthesizing important therapeutic compounds and this is discussed later in this chapter. The number of vital endogenous steps that have evolved for bacterial CYP function is still very small for instance, Biol in Bacillus subtilis is needed to produce biotin by a pathway distinct from other bacteria. Some CYPs, among the numerous forms uncovered, must be anticipated to be involved in key areas of endogenous metabolism especially in the... 

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