DSpace
 

DSpace at IIT Bombay >
IITB Publications >
Article >

Please use this identifier to cite or link to this item: http://dspace.library.iitb.ac.in/jspui/handle/10054/11995

Title: Biodegradation of phenanthrene by Pseudomonas sp strain PPD: purification and characterization of 1-hydroxy-2-naphthoic acid dioxygenase
Authors: DEVERYSHETTY, J
PHALE, PS
Keywords: gentisate 1,2-dioxygenase
crystal-structure
pseudaminobacter-salicylatoxidans
protocatechuate 3,4-dioxygenase
molecular characterization
catechol 2,3-dioxygenase
genetic-characterization
affinity chromatography
bacterial-degradation
phthalate isomers
Issue Date: 2009
Publisher: SOC GENERAL MICROBIOLOGY
Citation: MICROBIOLOGY-SGM, 155(), 3083-3091
Abstract: Pseudomonas sp. strain PPID can metabolize phenanthrene as the sole source of carbon and energy via the 'phthalic acid' route. The key enzyme, 1-hydroxy-2-naphthoic acid dioxygenase (1-HNDO, EC 1.13.11.38), was purified to homogeneity using a 3-hydroxy-2-naphthoic acid (3-H2NA)-affinity matrix. The enzyme was a homotetramer with a native molecular mass of 160 kDa and subunit molecular mass of similar to 39 kDa. It required Fe(II) as the cofactor and was specific for 1-hydroxy-2-naphthoic acid (1-H2NA), with K(m) 13.5 mu M and V(max) 114 mu mol min(-1) mg(-1). 1-HNDO failed to show activity with gentisic acid, salicylic acid and other hydroxynaphthoic acids tested. Interestingly, the enzyme showed substrate inhibition with a K(i) of 116 mu M. 1-HNDO was found to be competitively inhibited by 3-H2NA with a K(i) of 24 mu M. Based on the pH-dependent spectral changes, the enzyme reaction product was identified as 2-carboxybenzalpyruvic acid. Under anaerobic conditions, the enzyme failed to convert 1-H2NA to 2-carboxybenzalpyruvic acid. Stoichiometric studies showed the incorporation of 1 mol 02 into the substrate to yield 1 mol product. These results suggest that 1-HNDO from Pseudomonas sp. strain PPD is an extradiol-type ring-cleaving dioxygenase.
URI: http://dx.doi.org/10.1099/mic.0.030460-0
http://dspace.library.iitb.ac.in/xmlui/handle/10054/11995
http://hdl.handle.net/10054/11995
ISSN: 1350-0872
Appears in Collections:Article

Files in This Item:

There are no files associated with this item.

View Statistics

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

 

Valid XHTML 1.0! DSpace Software Copyright © 2002-2010  Duraspace - Feedback