Record Details

Allosteric NADP-glutamate dehydrogenase from aspergilli: purification, characterization and implications for metabolic regulation at the carbon-nitrogen interface

DSpace at IIT Bombay

View Archive Info
 
 
Field Value
 
Title Allosteric NADP-glutamate dehydrogenase from aspergilli: purification, characterization and implications for metabolic regulation at the carbon-nitrogen interface
 
Creator NOOR, S
PUNEKAR, NS
 
Subject ammonia assimilation
penicillium-chrysogenum
alpha-ketoglutarate
saccharomyces-cerevisiae
neurospora-crassa
gdha gene
nidulans
acid
fungi
involvement
 
Description NADP-dependent glutamate dehydrogenase (NADP-GDH) mediates fungal ammonium assimilation through reductive synthesis of glutamate from 2-oxoglutarate. By virtue of its position at the interface of carbon and nitrogen metabolism, biosynthetic NADP-GDH is a potential candidate for metabolic control. In order to facilitate characterization, a new and effective dye-affinity method was devised to purify NADP-GDH from two aspergilli, Aspergillus niger and Aspergillus nidulans. The A. niger NADP-GDH was characterized at length and its kinetic interaction constants with glutamate (K-m 34(.)7 mM) and ammonium (K-m 1(.)05 mM; K-i 0(.)4 mM) were consistent with an anabolic role. Isophthalate, 2-methyleneglutarate and 2,4-pyridinedicarboxylate were significant inhibitors, with respective K-i values of 6(.)9, 9(.)2 and 202(.)0 mu M. The A. niger enzyme showed allosteric properties and a sigmoid response (n(H) = 2(.)5) towards 2-oxoglutarate saturation. The co-operative behaviour was a feature common to NADP-GDH from Aspergillus awamori, A. nidulans and Aspergillus oryzae. NADP-GDH may therefore be a crucial determinant in adjusting 2-oxoglutarate flux between the tricarboxylic acid cycle and glutamate biosynthesis in aspergilli.
 
Publisher SOC GENERAL MICROBIOLOGY
 
Date 2011-08-29T06:23:57Z
2011-12-26T12:58:27Z
2011-12-27T05:48:26Z
2011-08-29T06:23:57Z
2011-12-26T12:58:27Z
2011-12-27T05:48:26Z
2005
 
Type Article
 
Identifier MICROBIOLOGY-SGM, 151(), 1409-1419
1350-0872
http://dx.doi.org/10.1099/mic.0.27751-0
http://dspace.library.iitb.ac.in/xmlui/handle/10054/11994
http://hdl.handle.net/10054/11994
 
Language en