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dc.contributor.authorDeveryshetty, Jaigeethen_US
dc.contributor.authorS. Phale, Prashanten_US
dc.contributor.editorJeff Coleen_US
dc.description.abstractAlcaligenes sp. strain PPH degrades phenanthrene via 1-hydroxy-2-naphthoic acid (1-H2NA), 1,2-dihydroxynaphthalene (1,2-DHN), salicylic acid and catechol. Enzyme activity versus growth profile and heat stability studies suggested the presence of two distinct hydroxylases, namely 1-hydroxy-2-naphthoic acid hydro- xylase and salicylate hydroxylase. 1-Hydroxy-2-naphthoic acid hydroxylase was partially purified (yield 48%, fold 81) and found to be a homodimer with a subunit molecular weight of $34 kDa. The enzyme was yellow in color, showed UV-visible absorption maxima at 274, 375 and 445 nm, and fluorescence emission maxima at 527 nm suggested it to be a flavoprotein. The apoenzyme prepared by the acid-ammonium sulfate (2 M) dialysis method was colorless, inactive and lost the characteristic flavin absorption spectra but regained $90% activity when reconstituted with FAD. Extraction of the prosthetic group and its analysis by HPLC suggests that the holoenzyme contained FAD. The enzyme was specific for 1-H2NA and failed to show activity with any other hydroxynaphthoic acid analogs or salicylic acid. The Km for 1-H2NA in the presence of either NADPH or NADH remained unaltered (72 and 75 mM, respectively), suggesting dual specificity for the coenzyme. The Km for FAD was determined to be 4.7 mM. The enzyme catalyzed the conversion of 1-H2NA to 1,2-DHN only under aerobic conditions. These results suggested that 1-hydroxy-2-naphthoic acid hydroxylase is a flavo- protein monooxygenase specific for 1-H2NA and different from salicylate-1- hydroxylase.en_US
dc.publisherBlackwell Publishing Ltd.en_US
dc.publisher.placeUnited Kingdomen_US
dc.relation.ispartofjournalFEMS Microbiology Lettersen_US
dc.subject.fieldofresearchStructural Biology (incl. Macromolecular Modelling)en_US
dc.titleBiodegradation of phenanthrene by Alcaligenes sp. strain PPH: partial purification and characterization of 1-hydroxy-2-naphthoic acid hydroxylaseen_US
dc.typeJournal articleen_US
dc.type.descriptionC1 - Peer Reviewed (HERDC)en_US
dc.type.codeC - Journal Articlesen_US
gro.hasfulltextNo Full Text

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