PMID:9659392
| Citation |
LiCata, VJ and Allewell, NM (1998) Solvent perturbation of the allosteric regulation of aspartate transcarbamylase. Biochim. Biophys. Acta 1384:306-14 |
|---|---|
| Abstract |
Escherichia coli aspartate transcarbamylase (ATCase) catalyzes the first committed step in pyrimidine biosynthesis, the condensation of aspartate and carbamyl phosphate. ATCase is positively allosterically regulated by ATP and negatively regulated by CTP. We have used mild solvent perturbation to gain global molecular information about the mechanism of heterotropic allostery. The [NaCl], temperature, and osmotic pressure dependence of the enzymatic activity of ATCase has been examined in the presence and absence of allosteric effectors. The results indicate that: 1) Regulation of aspartate binding by CTP appears to involve a unique set of electrostatic interactions not involved in enzyme function in the presence of ATP or in the absence of effectors. 2) Aspartate binding is enthalpically driven in the presence and absence of allosteric effectors. 3) The apparent enthalpy and entropy of aspartate binding (delta H, delta S), and activation energy of catalysis (Ea) are substantially altered in the presence of CTP but not ATP. 4) The change in hydration of ATCase upon substrate binding is the same in the presence and absence of allosteric effectors. 5) The linkage between heterotropic and homotropic allostery is different for ATP and CTP. |
| Links | |
| Keywords |
Adenosine Triphosphate/pharmacology; Allosteric Regulation; Aspartate Carbamoyltransferase/metabolism; Aspartic Acid/metabolism; Cytidine Triphosphate/pharmacology; Enzyme Activation; Escherichia coli/enzymology; Osmotic Pressure; Sodium Chloride/pharmacology; Solvents/pharmacology; Temperature |
| edit table |
Significance
You can help EcoliWiki by summarizing why this paper is useful
Useful Materials and Methods
You can help Ecoliwiki by describing the useful materials (strains, plasmids, antibodies, etc) described in this paper.
Annotations
<annotationlinks/>
EcoliWiki Links
Add links to pages that link here (e.g. gene, product, method pages)
References
See Help:References for how to manage references in EcoliWiki.