Evidence that bacterial cyanide oxygenase is a pterin-dependent hydroxylase

The soluble cell-free fraction (150,000 g high-speed supernatants [HSS]) of Pseudomonas fluorescens NUMB 11764 contains putative cyanide oxygenase (CN O) responsible for initiating cyanide oxidation and assimilation as a nitro genous growth substrate. CNO activity, assayed either by cyanide-dependent O-2 or NADH uptake, or by conversion of radioactive K-14 CN to (CO2)-C-14 w as detected at micromolar concentrations (apparent half-saturation constant , 4 muM). Results demonstrating that CNO requires a protein-enriched cell f raction and a low MW redox factor (< 500 Da) for which reduced biopterin co uld substitute are presented. The properties of CNO are consistent with tho se of a pterin hydroxylase. (C) 2001 Academic Press.