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<span style="font-size:14.0pt;font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";mso-ansi-language:EN-US;mso-fareast-language: EN-US;mso-bidi-language:AR-SA">Isolation and characterization of NADP<sup>+</sup> -linked isocitrate dehydrogenase of germinating pea seeds <i>(Pisum sativum)</i></span>

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Title Isolation and characterization of NADP+ -linked isocitrate dehydrogenase of germinating pea seeds (Pisum sativum)
 
Creator Srivastava, P K
Singh, D S
 
Description 335-341
NADP+- linked isocitrate dehydrogenase
(E.C.1.1.1.42) has been purified to homogeneity from germinating pea seeds. The
enzyme is a tetrameric protein (mol wt. about 146,000) made up of apparently
identical monomers (subunit mol wt, about 36,000). Thermal in activation of
purified enzyme at 45° and 50°C shows simple first order kinetics. The enzyme shows
optimum activity at pH range 7.5-8.
Effect of substrate [S] on enzyme activity at different pH (6.5-8) suggests that the proton behaves formally as an
"uncompetitive inhibitor". A basic group of the enzyme (site) is
protonated in this pH range in the
presence of substrate only, with a pKa equal to 6.78. On successive
dialysis against EDTA and phosphate

Buffer, pH
7.8 at O°C, yields an enzymatically inactive protein showing kinetics of
thermal inactivation identical to the untreated (native) enzyme. Maximum enzyme
activity is observed in presence of Mn2+ and Mg2+ ions
(3.75 mM). Addition
of Zn2+, Cd2+, C02+ and Ca2+
ions brings about partial recovery. Other metal ions Fe2+, Cu2+
and Ni2+ are ineffective.
 
Date 2012-12-25T18:38:53Z
2012-12-25T18:38:53Z
2001-10
 
Type Article
 
Identifier 0975-0959 (Online); 0301-1208 (Print)
http://hdl.handle.net/123456789/15313
 
Language en_US
 
Rights CC Attribution-Noncommercial-No Derivative Works 2.5 India
 
Publisher NISCAIR-CSIR, India
 
Source IJBB Vol.38(5) [October 2001]