Characterization of recombinant diaminopropionate ammonia-lyase from Escherichia coli and Salmonella typhimurium

Khan, Farida and Jala, Venkatakrishna R and Rao, Appaji N and Savithri, HS (2003) Characterization of recombinant diaminopropionate ammonia-lyase from Escherichia coli and Salmonella typhimurium. In: Biochemical and Biophysical Research Communications, 306 (4). 1083-1088 .

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Abstract

Diaminopropionate ammonia-lyase gene from Escherichia coli and Salmonella typhimurium was cloned and the overexpressed enzymes were purified to homogeneity. The k(cat) Values, determined for the recombinant enzymes with DL-DAP, D-serine, and L-serine as substrates, showed that the enzyme from S. typhimurium was more active than that from E coli and the K-m values were found to be similar. The purified enzymes had an absorption maximum (lambda(max)) at 412 nm, typical of PLP dependent enzymes. A red shift in lambda(max) was observed immediately after the addition Of 10 MM DL-DAP, which returned to the original lambda(max) of 412 nm in about 4 min. This red shift might reflect the formation of an external aldimine and/or other transient intermediates of the reaction. The apoenzyme of E coli and S. typhimurium prepared by treatment With L-cysteine could be partially (60%) reconstituted by the addition of PLP. The holo, apo, and the reconstituted enzymes were shown to be present as homo dimers by size exclusion chromatography. (C) 2003 Elsevier Science (USA). All rights reserved.

Item Type:	Journal Article
Publication:	Biochemical and Biophysical Research Communications
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	DAP ammonia-lyase;PLP dependent enzymes;Overexpression; Apoenzyme;Kinetics
Department/Centre:	Division of Biological Sciences > Biochemistry
Date Deposited:	08 Aug 2011 07:11
Last Modified:	08 Aug 2011 07:11
URI:	http://eprints.iisc.ac.in/id/eprint/39772

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