Characterization of dihydrolipoamide dehydrogenase from the mitochondria of Helicoverpa armigera, a pest resistant to insecticides

Akbar S., MD. and Jayalakshmi, S K and Sharma, H C and Sreeramulu, K (2011) Characterization of dihydrolipoamide dehydrogenase from the mitochondria of Helicoverpa armigera, a pest resistant to insecticides. Entomological Research, 41 (6). pp. 221-228. ISSN 1748-5967

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Abstract

Dihydrolipoamide dehydrogenase (DHLDH) was isolated from the mitochondria of Helicoverpa armigera, a destructive pest which has developed resistance to commonly used insecticides. The flavoenzyme was purified 17.98-fold to homogeneity with an overall yield of 10.53% by employing ammonium sulfate precipitation, hydroxylapatite chromatography and CM-Sephadex chromatography. The purified enzyme exhibited the specific activity of 18.7 U/mg and was characterized as a dimer with a subunit mass of 66 kDa. The enzyme showed specificity for nicotinamide adenine dinucleotide – hydrogen (NADH) and lipoamide, as substrates, with Michaelis-Menten constants (Km) of 0.083 mmol/L and 0.4 mmol/L, respectively. The reduction reaction of lipoamide by the enzyme could be explained by ping-pong mechanism. The spectra of DHLDH showed the maximum absorbance at 420 nm, 455 nm and 475 nm. The enzyme activity was strongly inhibited by mercurial and arsenical compounds. The N-terminal sequence of Ha-DHLDH showed homology with those of mammalian and arthropod DHLDH. Since H. armigera has developed high levels of resistance to commonly used insecticides, biochemical properties of the metabolic enzymes such as DHLDH, could be helpful to develop insecticidal molecules for the control of H. armigera, with a different mode of action.

Item Type: Article
Divisions: UNSPECIFIED
CRP: UNSPECIFIED
Uncontrolled Keywords: arsenical compounds;dihydrolipomide dehydrogenase;Helicoverpa armigera;mitochondria
Subjects: Others > Entomology
Depositing User: Mr Siva Shankar
Date Deposited: 27 Dec 2012 03:44
Last Modified: 27 Dec 2012 03:44
URI: http://oar.icrisat.org/id/eprint/6358
Official URL: http://dx.doi.org/10.1111/j.1748-5967.2011.00346.x
Projects: UNSPECIFIED
Funders: University of Agricultural Sciences, New Delhi, India
Acknowledgement: Providing a junior research fellowship under the scheme “Research Fellowship in Science for Meritorious Students” (RFSMS).
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