Allosteric serine hydroxymethyltransferase from monkey liver: Correlation of conformational changes caused by denaturants with the alterations in catalytic activity

Ramesh, Kashi S and Anantanarayanan, VS and Rao, Appaji N (1981) Allosteric serine hydroxymethyltransferase from monkey liver: Correlation of conformational changes caused by denaturants with the alterations in catalytic activity. In: Journal Of Biosciences, 3 (2). 167-178..

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Abstract

The far-ultraviolet region circular dichroic spectrumof serine hydroxymethyltransferase from monkey liver showed that the protein is in an α-helical conformation. The near ultraviolet circular dichoric spectrum revealed two negative bands originating from the tertiary conformational environment of the aromatic amino acid residues. Addition of urea or guanidinium chloride perturbed the characteristic fluorescence and far ultraviolet circular dichroic spectrum of the enzyme. The decrease in (θ)222 and enzyme activity followed identical patterns with increasing concentrations of urea, whereas with guanidinium chloride, the loss of enzyme activity preceded the loss of secondary structure. 2-Chloroethanol, trifluoroethanol and sodium dodecyl sulphate enhanced the mean residue ellipticity values. In addition, sodium dodecyl sulphate also caused a perturbation of the fluorescence emission spectrum of the enzyme. Extremes of pH decreased the – (θ)222 value. Plots of –(θ)222and enzyme activity as a function of pH showed maximal values at pH 7.4-7.5. These results suggested the prevalence of "conformational flexibility" in the structure of serine hydroxymethyltransferase.

Item Type:	Journal Article
Publication:	Journal Of Biosciences
Publisher:	Indian Academy Sciences
Additional Information:	Copyright of this article belongs to Indian Academy Sciences
Keywords:	Serine hydroxymethyltransferase; conformational changes; denaturants; fluorescence; circular dichroism; structure-activity relationship.
Department/Centre:	Division of Biological Sciences > Biochemistry
Date Deposited:	29 Sep 2009 09:16
Last Modified:	03 Aug 2011 10:35
URI:	http://eprints.iisc.ac.in/id/eprint/23577

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