Ochratoxin biosynthesis

Farber, P., and Geisen, R. (2004). Analysis of differentially-expressed ochratoxin A biosynthesis genes in Penicillium nordicum. Eur. J. Plant Pathol. 110, 661-669. 

Huff, W. E., and Hamilton, P. B. (1979). Mycotoxins - their biosynthesis in fungi Ochratoxins -metabolites of combined pathways. /. Food Prot. 42,815-820. 

Figure 11 Structures of ochratoxin A and C8-ochratoxin A-deoxyguanosine adduct (a) and biosynthesis of ochratoxin A (b).

Figure 2 Proposed ochratoxin-like biosynthesis ofXR587...

Romero SM, Alberto MR, Manca de Nadra MC, Vaamonde G (2009) Inhibition of growth and ochratoxin A biosynthesis in Aspergillus carbonarius by flavonoids and nonflavonoid compounds. Mycotox Res 25 165-170... 

Ochratoxin A (24). The main features of the biosynthesis of this hepatic myco-toxin were established by feeding experiments conducted withL-[ C]phenyl-alanine and sodium [2- C]acetate. Incorporation of these precursors into ochratoxin A (24) is in accord with the biosynthetic Scheme 9. 

The biosynthesis of ochratoxin A (158) has attracted a great deal of attention (88, 99, 180, 275, 307, 309, 321). The additional carbon at C-7 (a) is derived from the C-1 pool 321). The additional carbons (marked a) in oospolactone (23), oosponol (16) 214) and canescin (67) 36, 37) are similarly derived. However the origin of the remaining 3 carbons in the side chain of canescin remains unclear 37). 

De Jesus, A.E., P.S. Steyn, R. Vleggar, and P.L. Wessels Carbon-13 Nuclear Magnetic Resonance Assignments and Biosynthesis of the Mycotoxin Ochratoxin A.J. Chem. Soc. Perkin Trans. I 1980, 52. 

Maebayashi, Y., K. Miyaki, and M. Yamazaki Application of C-NMR to Biosynthetic Investigations. I. Biosynthesis of Ochratoxin A. Chem. Pharm. Bull. (Japan) 20, 2172 (1972). 

Carbon-13 Magnetic Resonance Assignments and Biosynthesis of Ochratoxin A. Tetrahedron Letters 1980, 993. 

The biosynthesis of ochratoxin A has been studied using both and C-labeled precursors. In preliminary studies, Ferreira and Pitout (1969) showed that DL-[l- C]-jS-phenylalanine was incorporated into ochratoxin A by cultures of A. ochraceus. Hydrolysis of the labeled ochratoxin A with 6 N hydrochloric acid gave the isocoumarin acid 7 and L-jS-phenylalanine. The amino acid was found to contain all the activity. These results were confirmed by Steyn et al. (1970) and Maebayashi et al. (1972) using L-[f/- C]- -phenylalanine, as well as by Searcy et al. (1969) using [1- " C]-jS-phenylalanine. 

Incubation of A. ochraceus in a medium containing sodium [ Cljchloride resulted in the incorporation (0.75%) of Cl into ochratoxin A (Wei et al., 1971). It has not been established at what point in the biosynthesis of ochratoxin A the chlorine atom is introduced. 

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