Biodegradation of phenanthrene by Pseudomonas sp strain PPD: purification and characterization of 1-hydroxy-2-naphthoic acid dioxygenase

DSpace/Manakin Repository

Biodegradation of phenanthrene by Pseudomonas sp strain PPD: purification and characterization of 1-hydroxy-2-naphthoic acid dioxygenase

Show full item record

Title: Biodegradation of phenanthrene by Pseudomonas sp strain PPD: purification and characterization of 1-hydroxy-2-naphthoic acid dioxygenase
Author: DEVERYSHETTY, J; PHALE, PS
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
Date: 2009


Files in this item

Files Size Format View

There are no files associated with this item.

This item appears in the following Collection(s)

Show full item record

Search DSpace


Advanced Search

Browse

My Account