Title: [29] Active site-specific reagents and transition-state analogs for enolase
Abstract: This chapter describes the active site-specific reagents and transition-state analogs for enolase. There is only one active site-specific reagent known to form a covalent derivative with the enzyme— namely, glycidol phosphate (1,2- epoxipropanol 3-phosphate). In addition, there are pairs of analogs, D-tartronate semialdehyde 2-phosphate and 3-amino enolpyruvate phosphate, which form very tight noncovalent complexes with the active site of enolases. Because of the strong UV absorbance of the complexes, these compounds have been useful in establishing the number of active sites in the enzyme, and as likely transition state analogs, their interaction with the enzyme has shed some light on the mechanism of catalysis. Glycidol phosphate is readily prepared by phosphorylation of commercially available glycidol with POC13, and it satisfies the major requirements for an active site-specific reagent for rabbit muscle enolase. The chapter describes dissociation constants and stoichiometry of enolase-inhibitor complexes, the spectral properties of the enolase inhibitors tartronate semialdehyde phosphate (Ttal 2P) and 3-amino enolpyruvate, and the synthesis of Ttal 2P from commercially available D-gluconolactone. A representation of the complexes of Ttal 2P and Am-ePrvP with the active site of enolase is given as a basis for the comparison with the proposed transition state in the reversible dehydration of glycerate 2-phosphate to enolpyruvate phosphate. It is shown that the enolase-analog complexes form only in the presence of Mg2+ and that both compounds compete with substrate for the active site support the proposition that the two compounds behave as true substrate (transition state) analogs.
Publication Year: 1975
Publication Date: 1975-01-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
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Cited By Count: 1
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