TRXR) chromosomal position 12q23.3-q24.1 (§, ‡) is a homodimeric selenocysteine-containing enzyme. Secys a selenocysteine residue is an essential TR isozyme component, located near the C-terminus region [cysteine (Cys)-497,Secys-498] of the intracellular, redox cellular environments center in the catalytically active enzyme site, Gly-499 is the actual C-terminal amino acid. In their N-terminal ...

Simple strategies for using alkene reductase enzymes to produce gram-scale quantities of both (R)- and (S)-citronellal have been developed. The methodology is easily accessible to non-specialist laboratories, allowing alkene reductases to be added to the toolbox of routine synthetic transformations.

A novel trimethoprim resistance gene, designated dfrK, was detected in close proximity to the tetracycline resistance gene tet(L) on the ca. 40-kb plasmid pKKS2187 in a porcine methicillin (meticillin)-resistant Staphylococcus aureus isolate of sequence type 398. The dfrK gene encodes a 163-amino-acid dihydrofolate reductase that differs from all so-far-known dihydrofolate reductases.

To understand the mechanisms underlying the increased N2O reductase activity in the Bradyrhizobium japonicum 5M09 mutant from enrichment culture under N2O respiration, we analyzed the expression of genes encoding denitrification reductases and regulators. Our results suggest a common regulation of nap (encoding periplasmic nitrate reductase) and nos (encoding N2O reductase).

Bacillus subtilis can use either nitrate or nitrite as a sole source of nitrogen. The isolation of the nasABCDEF genes of B. subtilis, which are required for nitrate/nitrite assimilation, is reported. The probable gene products include subunits of nitrate/nitrite reductases and an enzyme involved in the synthesis of siroheme, a cofactor for nitrite reductase.

2-Arylpropionic acid derivatives, such as ibuprofen, constitute an important group of non-steroidal anti-inflammatory drugs (NSAIDs). Biocatalytic asymmetric reduction 2-arylacrylic derivatives by ene reductases (EREDs) is a valuable approach for synthesis these derivatives. However, previous bioreduction EREDs resulted solely in nonpharmacological (R)-enantiomers. Here, we present the engineer...

Ribonucleotide reductase (RNR) is a key enzyme that mediates the synthesis of deoxyribonucleotides, the DNA precursors, for DNA synthesis in every living cell. This enzyme converts ribonucleotides to deoxyribonucleotides, the building blocks for DNA replication, and repair. Clearly, RNR enzymes have contributed to the appearance of genetic material that exists today, being essential for the evo...

Introduction Quinones are ubiquitous dietary compounds. Reduction of quinones by one-electron reduction systems (cytochrome P450 reductases) results in the formation of reactive semiquinones that can be re-oxidized to quinones by molecular oxygen with the formation of superoxide radical (02-*). Superoxide can lead to the formation of other reactive oxygen species, including the highly mutagenic...

The effects of an oral administration of carbon tetrachloride on various liver microsomal and supernatant components were studied 1hr. and 2hr. after dosing. The modifications of such early changes resulting from a concomitant administration of promethazine together with the carbon tetrachloride were also investigated. The microsomal components studied were: cytochromes P-450 and b(5); inorgani...

Complex life on our planet crucially depends on strong redox disequilibria afforded by the almost ubiquitous presence of highly oxidizing molecular oxygen. However, the history of O2-levels in the atmosphere is complex and prior to the Great Oxidation Event some 2.3 billion years ago, the amount of O2 in the biosphere is considered to have been extremely low as compared with present-day values....