No abstract

Many enzymes contain a nondiffusible organic cofactor, often termed a prosthetic group, which is located in the active site and essential for the catalytic activity of the enzyme. These cofactors can often be extracted from the protein to yield the respective apoenzyme, which can subsequently be reconstituted with an artificial analogue of the native cofactor. Nowadays a large variety of synthetic cofactors can be used for the reconstitution of apoenzymes and, thus, generate novel semisynthetic enzymes. This approach has been refined over the past decades to become a versatile tool of structural enzymology to elucidate structure-function relationships of enzymes. Moreover, the reconstitution of apoenzymes can also be used to generate enzymes possessing enhanced or even entirely new functionality. This Review gives an overview on historical developments and the current state-of-the-art on apoenzyme reconstitution.

No abstract

No abstract

No abstract

Functionalized cyclic vinyl sulfones were directly converted to the "polarity reversed" vinyl phosphonates through an efficient one pot procedure. Ozonolysis of these vinyl sulfones and vinyl phosphonates furnish complementary sets of termini-differentiated ester-aldehydes. This strategy has been applied for preparation of segments needed for the synthesis of Aplyronine A. The scope and limitations of this transformation were defined.

No abstract

The biodegradation of organic compounds present in water at trace concentration has become a critical environmental problem. In particular, enzymatic oxidation by fungal laccases offers a promising alternative for efficient and sustainable removal of organic pollutants in water. In this work, the biocatalytic ability of laccases from the Pycnoporus sanguineus CS43 fungus was evaluated. A filtered culture supernatant (laccase cocktail) evidenced an enhanced biotransformation capability to remove common endocrine-disruptor compounds (EDCs), such as bisphenol A, 4-nonylphenol, 17-α-ethynylestradiol and triclosan. A biodegradation of around 89–100 % was achieved for all EDCs using synthetic samples (10 mg L−1) and after the enzymatic treatment with 100 U L−1 (50.3 U mg −1). The biodegradation rates obtained were fitted to a first order reaction. Furthermore, enzymatic biocatalytic activity was also evaluated in groundwater samples coming from northwestern Mexico, reaching biotransformation percentages between 55 and 93 % for all tested compounds. As far as we know this is the first study on real groundwater samples in which the enzymatic degradation of target EDCs by a laccase cocktail from any strain of Pycnoporus sanguineus was evaluated. In comparison with purified laccases, the use of cocktail offers operational advantages since additional purification steps can be avoided.