Properties of NADP+-malic enzyme from pod walls of chickpea (Cicer arietinum)

Das, Suchitra ; Sood, D. R. ; Sawhney, S. K. ; Singh, Randhir (1986) Properties of NADP+-malic enzyme from pod walls of chickpea (Cicer arietinum) Physiologia Plantarum, 68 (2). pp. 308-314. ISSN 0031-9317

Full text not available from this repository.

Official URL: http://onlinelibrary.wiley.com/doi/10.1111/j.1399-...

Related URL: http://dx.doi.org/10.1111/j.1399-3054.1986.tb01931.x

Abstract

NADP+-malic enzyme (l-malate: NADP+ oxidoreductase, decarboxylating EC 1.1.1.40) from pod walls of chickpea was purified 51-fold by ammonium sulphate fractionation, DEAE- cellulose chromatography and gel filtration through Sepharose 4B. The purified enzyme required a divalent cation, either Mn2+ or Mg2+, for its activity. Km values at pH 7.8 for malate, NADP+ and Mn2+ were 4.0, 0.031 and 0.71 mM, respectively. Mn2+-dependent activity was inhibited by heavy metal ions such as Cd2+, Zn2+, Hg2+, and to a lesser extent by Pb2+ and Al3+. Among the organic acids examined, sodium salts of oxalate and oxaloacetate were inhibitory. Kinetics of the reaction mechanism showed sequential binding of malate and NADP+ to the enzyme. Products of reaction, viz. pyruvate, bicarbonate and NADPH, inhibited the enzyme activity. At limiting concentrations of NADP+, pyruvate and bicarbonate induced a positive cooperative effect by malate. It is proposed that the activity of NADP+-malic enzyme is controlled by intracellular concentrations of substrates and products.

Item Type:Article
Source:Copyright of this article belongs to John Wiley and Sons.
Keywords:NADP+-malic Enzyme; Regulation; Pod Walls
ID Code:50071
Deposited On:21 Jul 2011 14:40
Last Modified:21 Jul 2011 14:40

Repository Staff Only: item control page