Mixed disulphide formation in the presence of oxidized glutathione reversibly inactivates rabbit skeletal muscle aldolase. Inactivation is allosteric, preferentially modifying Cys-72 on the surface of the aldolase homotetramer distant from active-site locations and subunit interfaces. Ion-exchange chromatography fractionates partly inactivated aldolase into three distinct enzymic species: unmod...

A highly efficient water-tolerant, solid-base catalyst for the self-condensation of biomass-derived methyl ketones to jet-diesel fuel precursors was developed by grafting site-isolated secondary amines on silica-alumina supports. It is shown that apart from the nature and density of amine groups and the spatial separation of the acidic and basic sites, the acidity of the support material plays ...

Small (24-35 amino acid residues) peptides that catalyze carbon-carbon bond transformations including aldol, retro-aldol, and Michael reactions in aqueous buffer via an enamine mechanism have been developed. Peptide phage libraries were created by appending six randomized amino acid residues to the C-terminus or to the N-terminus of an 18-mer alpha-helix peptide containing lysine residues. Reac...

Metal complexes carrying a new class of singlet carbene ligands stabilized by lateral enamine moieties are accessible by oxidative insertion into readily available chloro vinamidinium salts.

Treatment of 3-formylacetylacetone with the amines benzylamine, tert -butylamine and ( S )-methylbenzylamine led to formation corresponding Schiff bases 3-[(benzylamino)methylidene]pentane-2,4-dione, C 13 H 15 NO 2 1 ), 3-[( -butylamino)methylidene]pentan-2,4-dione, 10 17 ) 3-{[( )-benzyl(methyl)amino]methylidene}pentane-2,4-dione, 14 3 ). The molecules all three compounds exist as enamine taut...

The Nenitzescu reaction is a condensation between an enamine and quinone, which can give rise to wide variety of products depending on the nature starting material conditions. most commonly observed are 5-hydroxyindoles 5-hydroxybenzofurans. Both classes interest since they known possess promising bioactivities. Despite high chemodivergency for this reaction, it remains interesting synthetic st...

The enzyme 4-oxalocrotonate tautomerase (4-OT) is part of a catabolic pathway for aromatic hydrocarbons in Pseudomonas putida mt-2, where it catalyzes the conversion of 2-hydroxy-2,4-hexadienedioate(1) to 2-oxo-3-hexenedioate(2). 4-OT is a member of the tautomerase superfamily, a group of homologous proteins that are characterized by a β-α-β structural fold and a catalytic amino-terminal prolin...

We identify the cyanogenic substrate for horseradish peroxidase (HRP) as a conjugated enamine and explore this unusual reaction using alpha-aminocinnamate (RH) as follows. 1) HRP catalyzes the oxidation of RH by O2 (and its peroxidation by H2O2 to form R-R) to produce, simultaneously, CN- and benzaldehyde cyanohydrin. 2) RH is transient and must be generated in situ. The properties of the cyano...

The use of sonochemistry is described in the organocatalytic enamine-azide [3 + 2] cycloaddition between 1,3-diketones and aryl azidophenyl selenides. These sonochemically promoted reactions were found to be amenable to a range of 1,3-diketones or aryl azidophenyl selenides, providing an efficient access to new ((arylselanyl)phenyl-1H-1,2,3-triazol-4-yl)ketones in good to excellent yields and s...