Record Details

Delineation of an in vivo inhibitor for Aspergillus glutamate dehydrogenase

DSpace at IIT Bombay

View Archive Info
 
 
Field Value
 
Title Delineation of an in vivo inhibitor for Aspergillus glutamate dehydrogenase
 
Creator CHOUDHURY, R
NOOR, S
VARADARAJALU, LP
PUNEKAR, NS
 
Subject saccharomyces-cerevisiae
competitive-inhibition
molecular-interactions
nidulans
acid
purification
niger
synthetase
metabolism
synthase
glutamate dehydrogenase
isophthalate
dimethylisophthalate
in vivo inhibition
cross-over analysis
nitrogen metabolism
aspergillus
 
Description NADP-glutamate dehydrogenase (NADP-GDH) along with glutamine synthetase plays a pivotal role in ammonium assimilation. Specific inhibitors were valuable in defining the importance of glutamine synthetase in nitrogen metabolism. Selective in vivo inhibition of NADP-GDH has so far been an elusive desideratum. Isophthalate, a potent in vitro inhibitor of Aspergillus niger NADP-GDH [Noor S, Punekar NS. Allosteric NADP-glutamate dehydrogenase from aspergilli: purification, characterization and implications for metabolic regulation at the carbon-nitrogen interface. Microbiology 2005;151:1409-19], was evaluated for its efficacy in vivo. Dimethyl ester of isophthalate (DMIP), but not isophthalate, inhibited A. niger growth on agar as well as in liquid culture. This was ascribed to the inability of isophthalate to enter fungal mycelia. Subsequent to DMIP addition however, intracellular isophthalate could be demonstrated. Apart from NAD-GDH, no other enzyme including NAD-glutamate synthase was inhibited by isophthalate. A cross-over at NADP-GDH step of metabolism was observed as a direct consequence of isophthalate (formed in vivo from DMIP) inhibiting this enzyme. Addition of ammonium to DMEP-treated A. niger mycelia resulted in intensive vacuolation, retraction of cytoplasm and autolysis. Taken together, these results implicate glutamate dehydrogenase and NADP-GDH in particular, as a key target of in vivo isophthalate inhibition during ammonium assimilation. (C) 2007
 
Publisher ELSEVIER SCIENCE INC
 
Date 2011-07-27T08:00:51Z
2011-12-26T12:56:23Z
2011-12-27T05:45:04Z
2011-07-27T08:00:51Z
2011-12-26T12:56:23Z
2011-12-27T05:45:04Z
2008
 
Type Article
 
Identifier ENZYME AND MICROBIAL TECHNOLOGY, 42(2), 151-159
0141-0229
http://dx.doi.org/10.1016/j.enzmictec.2007.08.011
http://dspace.library.iitb.ac.in/xmlui/handle/10054/7164
http://hdl.handle.net/10054/7164
 
Language en