Studies on nucleotidases in plants : Reversible denaturation of the crystalline mung bean nucleotide pyrophosphatase and the effect of adenylates on the native and renatured enzyme

Balakrishnan, CV and Ravindranath, SD and Rao, N Appaji (1974) Studies on nucleotidases in plants : Reversible denaturation of the crystalline mung bean nucleotide pyrophosphatase and the effect of adenylates on the native and renatured enzyme. In: Archives of Biochemistry and Biophysics, 164 (1). pp. 156-164.

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Abstract

The crystalline mung bean nucleotide pyrophosphatase was inhibited nonlinearly by AMP, one of the products of the reaction. The partially inactive enzyme was specifically reactivated by ADP, and V at maximal activation was the same as that of the native enzyme. ATP was a linear, noncompetitive inhibitor. The kinetic evidence suggested that ADP and ATP might not be reacting at the same site as AMP. The electrophoretic mobility of the enzyme was increased by AMP, whereas ADP and ATP were without effect. The enzyme was denatured on treatment with urea or guanidine hydrochloride. The renatured and the native enzyme had the same pH (9.4) and temperature (49 °C) optimum. The Km (0.2 mImage ) and V (3.2) of the native enzyme increased on renaturation to 1.8 mImage and 8.0, respectively. In addition, renaturation resulted in desensitization of the enzyme to inhibition by low concentrations of AMP. Renaturation did not affect the reactivation of the apoenzyme by Zn2+.

Item Type:	Journal Article
Publication:	Archives of Biochemistry and Biophysics
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Department/Centre:	Division of Biological Sciences > Biochemistry
Date Deposited:	22 Dec 2009 09:48
Last Modified:	19 Sep 2010 05:44
URI:	http://eprints.iisc.ac.in/id/eprint/23154

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