A Labeling Study To Elucidate the Biosynthesis of 4-(4-Hydroxyphenyl)-Butan-2-one (Raspberry Ketone) by Nidula niveo-tomentosa.

Submerged cells of the basidiomycete Nidula niveo-tomentosa; a microbial producer of 4-(4-hydroxyphenyl)butan-2-one, were supplemented with [sup 13]C-labeled L-phenylalanines and with [1-[sup 13]C]glucose. Labeled transformation products were detected by a novel method of analyzing stable isotope-labeled metabolites, gas chromatography (GC) coupled to an atomic emission detector, and by GC-mass spectrometry. A benzoate moiety was side chain elongated according to the poly-β-keto scheme. The presence of an acetyl coenzyme A-carboxylase inhibitor shifted the spectrum of products to benzyl compounds. Hence, the fungal pathway differs from the one established for plant tissues. [ABSTRACT FROM AUTHOR]