Agrobacterium tumefaciens strain C58 can utilize d-galacturonate as a sole source of carbon via a pathway in which the first step is oxidation of d-galacturonate to D-galactaro-1,5-lactone. We have identified a novel enzyme, D-galactarolactone isomerase (GLI), that catalyzes the isomerizaton of D-galactaro-1,5-lactone to D-galactaro-1,4-lactone. GLI, a member of the functionally diverse amidohy...

Pironetin is a natural product with potent antiproliferative activity that forms a covalent adduct with α-tubulin via conjugate addition into the natural product's α,β-unsaturated lactone. Although pironetin's α,β-unsaturated lactone is involved in its binding to tubulin, the structure-activity relationship at different positions of the lactone have not been thoroughly evaluated. For a systemat...

Weeds pose major constraints in crop production. The use of allelochemicals and allelopathic species can provide an effective alternative for sustainable weed management. In a previous study that evaluated the activity wild cultivated plants Turkey, Hibiscus sabdariffa demonstrated strongest inhibitory potential. This aimed to estimate phytotoxic influence H. water crude extracts on Lactuca sat...

• Alkyl orthoformates and acetals promote esterification of levulinic acid. Reaction proceeds through formation a pseudo lactone intermediate. Inexpensive commercial catalysts are highly effective in levulinate ester formation. Highly acidic selectively produce products. Moderately nanoporous silicates the lactone. The acid under conditions to esters is current significant interest due potentia...

Two sensitive reversed-phase high-performance liquid chromatographic fluorescence methods, with simple sample handling at the site of the patient, are described for the determination of the lactone and lactone plus carboxylate forms of 9-aminocamptothecin (9AC). For 9AC lactone, the sample preparation was a liquid-liquid extraction with acetonitrile-n-butyl chloride (1:4, v/v), whereas the samp...

We report the first experimental observation that a clinically important camptothecin [CPT; topotecan (TPT), a water-soluble CPT] binds directly and noncovalently to double-stranded DNA and single-stranded DNA structures in the absence of topoisomerase I, but only in the lactone form. We observed clear DNA sequence specificity of the TPT lactone binding to duplex DNA, which was comprised of alt...

In the title compound, C15H16O6, obtained from the acyl-ation reaction between 2,3-O-iso-propyl-idene-d-ribono-1,4-lactone and benzoyl chloride, the known absolute configuration for the lactone moiety of the ester substituent has been confirmed. The five-membered rings of the bicyclic lactone-dioxolane moiety both show envelope conformations and form a dihedral angle of 19.82 (7)° between the l...

The inability of humans to synthesize L-ascorbic acid is known to be due to a lack of L-gulono-gamma-lactone oxidase, an enzyme that is required for the biosynthesis of this vitamin. Isolation of a cDNA for rat L-gulono-gamma-lactone oxidase allowed us to study the basic defect underlying this deficiency at the gene level and led to isolation of a human genomic clone related to L-gulono-gamma-l...