Aroma of peas, its constituents and reduction strategies - Effects from breeding to processing.

Peas as an alternative protein source have attracted a great deal of interest from the food industry and consumers in recent years. However, pea proteins usually do not taste neutral and exhibit a distinct flavor, often characterized as "beany". This is usually contrasted by the food industry's desire for sensory neutral protein sources.

Genetic Engineering of an Artificial Metalloenzyme for Transfer Hydrogenation of a Self-Immolative Substrate in Escherichia coli's Periplasm.

Artificial metalloenzymes (ArMs), which combine an abiotic metal cofactor with a protein scaffold, catalyze various synthetically useful transformations. To complement the natural enzymes' repertoire, effective optimization protocols to improve ArM's performance are required. Here we report on our efforts to optimize the activity of an artificial transfer hydrogenase (ATHase) using Escherichia coli whole cells.

Directed evolution of artificial metalloenzymes for in vivo metathesis.

The field of biocatalysis has advanced from harnessing natural enzymes to using directed evolution to obtain new biocatalysts with tailor-made functions. Several tools have recently been developed to expand the natural enzymatic repertoire with abiotic reactions. For example, artificial metalloenzymes, which combine the versatile reaction scope of transition metals with the beneficial catalytic features of enzymes, offer an attractive means to engineer new reactions.

Investigation of excess-electron transfer in DNA double-duplex systems allows estimation of absolute excess-electron transfer and CPD cleavage rates.

To investigate the parameters and rates that determine excess-electron transfer processes in DNA duplexes, we developed a DNA double-duplex system containing a reduced and deprotonated flavin donor at the junction of two duplexes with either the same or different electron acceptors in the individual duplex substructures. This model system allows us to bring the two electron acceptors in the duplex substructures into direct competition for injected electrons and this enables us to decipher how the kind of acceptor influences the transfer data. Measurements with the electron acceptors 8-bromo-dA (BrdA), 8-bromo-dG (BrdG), 5-bromo-dU (BrdU), and a cyclobutane pyrimidine dimer, which is a UV-induced DNA lesion, allowed us to obtain directly the maximum overall reaction rates of these acceptors and especially of the T=T dimer with the injected electrons in the duplex.

Efficient synthesis of 5-hydroxymethylcytosine containing DNA.

5-Hydroxymethylcytosine ((5-HOMe)dC) was recently discovered as the sixth base in the mammalian genome. The development of a new phosphoramidite building block is reported, which allows efficient synthesis of (5-HOMe)dC containing DNA. Key steps of the synthesis are a palladium-catalyzed formylation and the simultaneous protection of a hydroxyl and amino group as a cyclic carbamate.

A new ground state single electron donor for excess electron transfer studies in DNA.

A new photoinducible single electron donor has been developed, which, when linked to thymidine, is shown to be an efficient ground state reducing agent in DNA; the donor can be activated at wavelengths where standard DNA does not absorb.

Bisubstrate inhibitors of catechol O-methyltransferase (COMT): the crucial role of the ribose structural unit for inhibitor binding affinity.

Inhibition of the enzyme catechol O-methyltransferase offers a therapeutic handle to regulate the catabolism of catecholamine neurotransmitters, providing valuable assistance in the treatment of CNS disorders such as Parkinson's disease. A series of ribose-modified bisubstrate inhibitors of COMT featuring 2'-deoxy-, 3'-deoxy-, 2'-aminodeoxy-3'-deoxy-, and 2'-deoxy-3'-aminodeoxyribose-derived central moieties and analogues containing the carbocyclic skeleton of the natural product aristeromycin were synthesized and evaluated to investigate the molecular recognition properties of the ribose binding site in the enzyme. Key synthetic intermediates in the ribose-derived series were obtained by deoxygenative [1,2]-hydride shift rearrangement of adenosine derivatives; highlights in the synthesis of carbocyclic aristeromycin analogues include a diastereoselective cyclopropanation step and nucleobase introduction with a modified Mitsunobu protocol.