NISCAIR Online Periodicals Repository

NISCAIR ONLINE PERIODICALS REPOSITORY (NOPR)  >
NISCAIR PUBLICATIONS >
Research Journals >
Indian Journal of Biochemistry and Biophysics (IJBB) >
IJBB Vol.43 [2006] >
IJBB Vol.43(6) [December 2006] >


Title: Mechanism of inhibition of Ca2+-transport activity of sarcoplasmic reticulum
Authors: Pang, Yuhong
Li, Xiaozhu
Qin, Sanbo
Zhang, Hongjie
Chen, Jianwen
Keywords: Anisodamine
Sarcoplasmic reticulum
Ca2+-ATPase
Ca2+-transport activity
ANS binding fluorescence
Conformational change
Issue Date: 2006
Publisher: CSIR
Abstract: The mechanism of inhibition of Ca2+-transport activity of rabbit sarcoplasmic reticulum Ca2+-ATPase (SERCA) by anisodamine (a drug isolated from a medicinal herb Hyoscyamus niger L) was investigated by using ANS (1-anilino-8-naphthalenesulfonate) fluorescence probe, intrinsic fluorescence quenching and Ca2+-transport activity assays. The number of ANS binding sites for apo Ca2+-ATPase was determined as 8, using a multiple-identical binding site model. Both anisodamine and Ca2+ at millimolar level enhanced the ANS binding fluorescence intensities. Only anisodamine increased the number of ANS molecules bound by SERCA from 8 to 14. The dissociation constants of ANS to the enzyme without any ligand, with 30 mM anisodamine and with 15 mM Ca2+ were found to be 53.0 μM, 85.0 μM and 50.1 μM, respectively. Both anisodamine and Ca2+ enhanced the ANS binding fluorescenc with apparent dissociation constants of 7.6 mM and 2.3 mM, respectively, at a constant concentration of the enzyme. Binding of anisodamine significantly decreased the binding capacity of Ca2+ with the dissociation constant of 9.5 mM, but binding of Ca2+ had no obvious effect on binding of anisodamine. Intrinsic fluorescence quenching and Ca2+-transport activity assays gave the dissociation constants of anisodamine to SERCA as 9.7 and 5.4 mM, respectively, which were consistent with those obtained from ANS-binding fluorescence changes during titration of SERCA with anisodamine and anisodamine + 15 mM Ca2+, respectively. The results suggest that anisodamine regulates Ca2+-transport activity of the enzyme, by stabilizing the trans-membrane domain in an expanded, inactive conformation, at least at its annular ring region.
Page(s): 351-359
ISSN: 0301-1208
Source:IJBB Vol.43(6) [December 2006]

Files in This Item:

File Description SizeFormat
IJBB 43(6) 351-359.pdf402.18 kBAdobe PDFView/Open
 Current Page Visits: 915 
Recommend this item

 

National Knowledge Resources Consortium |  NISCAIR Website |  Contact us |  Feedback

Disclaimer: NISCAIR assumes no responsibility for the statements and opinions advanced by contributors. The editorial staff in its work of examining papers received for publication is helped, in an honorary capacity, by many distinguished engineers and scientists.

CC License Except where otherwise noted, the Articles on this site are licensed under Creative Commons License: CC Attribution-Noncommercial-No Derivative Works 2.5 India

Copyright © 2012 The Council of Scientific and Industrial Research, New Delhi. All rights reserved.

Powered by DSpace Copyright © 2002-2007 MIT and Hewlett-Packard | Compliant to OAI-PMH V 2.0

Home Page Total Visits: 639187 since 06-Feb-2009  Last updated on 15-Dec-2014Webmaster: nopr@niscair.res.in