gamma-L-[H-3]-Glutaminyl-4-[C-14]hydroxybenzene (GHB): biosynthesis and metabolic fate after applying on Agaricus bisporus

gamma-L-[H-3]-Glutaminyl-4-[C-14]hydroxybenzene (doubly labelled GHB), a ph enolic amino acid characteristic of the Agaricus genus, was synthesized by feeding direct precursors such as 4-[U-C-14]aminophenol and L-[U-H-3]glutam ic acid to mushroom gills. Radiolabelled compounds, namely mannitol, glutam ine and doubly labelled GHB, were applied onto different tissues of growing sporophore and mycelium to follow their possible translocation into fruit body. Following contact with mushroom enzymes, doubly labelled GHB was imme diately cleaved into its two components; the aromatic moiety was mainly con sumed and lot as CO2. This result was confirmed by applying 4-[U-C-14]amino phenol on both gl owing mushroom and sterile mycelium, which led to the rec overy of the radiolabel as (CO2)-C-14. (C) 1998 Elsevier Science Ltd. All r ights reserved.