title: Patulin biosynthesis: the metabolism of m-hydroxybenzyl alcohol and m-hydroxybenzaldehyde by particulate preparations from Penicillium patulum.
abstract: The ring hydroxylation of m-hydroxybenzyl alcohol to gentisyl alcohol by a particulate preparation from Penicillium patulum has been characterised. The activity was shown to be closely associated with, but not necessarily identical to, m-cresol 2-hydroxylase activity of the 105 000 X g microsomal fraction. As with both the m-cresol hydroxylases of this system, m-hydroxybenzyl alcohol hydroxylase required oxygen and NADPH for activity. A Km value for m-hydroxybenzyl alcohol of 15 muM was measured. Inhibition of the hydroxylase activity and its reversal by light, as well as the action of cytochrome c, KCN and other effectors suggested a mixed-function oxidase reaction of the cytochrome P-450, NADPH-cytochrome reductase type. m-Hydroxybenzaldehyde was not ring hydroxylated by any preparation from P. patulum. Apart from the previously described conversion to m-hydroxybenzyl alcohol by a predominantly soluble dehydrogenase, m-hydroxybenzaldehyde was metabolized to m-hydroxybenzoic acid by a particulate fraction. This activity required NADPH. It was concluded that the main biosynthetic pathway to patulin must be through m-hydroxybenzyl alcohol, gentisyl alcohol and gentisaldehyde.
mesh_terms: D001547:Benzaldehydes / Q000378:metabolism*; D001592:Benzyl Alcohols / Q000096:biosynthesis / Q000378:metabolism*; D001593:Benzyl Compounds / Q000378:metabolism*; D002248:Carbon Monoxide / Q000494:pharmacology; D003408:Cresols; D003486:Cyanides / Q000494:pharmacology; D003574:Cytochrome c Group / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D006912:Hydroxyquinolines / Q000096:biosynthesis; D007700:Kinetics; D008027:Light; D008861:Microsomes / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000378:metabolism; D009243:NAD / Q000494:pharmacology; D010101:Oxygen Consumption; D010365:Patulin / Q000096:biosynthesis*; D010407:Penicillium / Q000378:metabolism*; D011714:Pyrans / Q000096:biosynthesis*; D013347:Subcellular Fractions / Q000201:enzymology
chemical_list: D001547:Benzaldehydes; D001592:Benzyl Alcohols; D001593:Benzyl Compounds; D003408:Cresols; D003486:Cyanides; D003574:Cytochrome c Group; D006912:Hydroxyquinolines; D011714:Pyrans; D009243:NAD; C011276:3-hydroxybenzyl alcohol; D002248:Carbon Monoxide; C011275:3-hydroxybenzaldehyde; D010365:Patulin; D006899:Mixed Function Oxygenases