Vitamin K is a nutrient that was originally identified as an essential factor for blood coagulation. Recently, vitamin K has emerged as a potential protector against osteoporosis, atherosclerosis, and hepatocarcinoma. Accumulated evidence indicates that subclinical non-hemostatic vitamin K deficiency in extrahepatic tissues, particularly in bone and possibly in vasculature, exists widely in the...

Drawing on independent work carried out by academic and industrial researchers using the immobilized TEMPO catalyst Silia Cat TEMPO, in this study, we show how shifting carboxylation process mediated solution to a above-mentioned hybrid sol–gel allows synthesis of insoluble polysaccharide nanofibers superior quality, eliminating waste.

A method for the synthesis of α-amino acids by direct reductive carboxylation of aromatic imines with CO2 is described. The protocol employs readily available commercial reagents and serves as a one-step alternative to the Strecker synthesis.

Osteocalcin (OCN) is a small noncollagenous protein mainly produced by osteoblasts and is highly represented in bones of most vertebrates. Human OCN contains up to three gamma-carboxyglutamic acid (Gla-OCN) residues at positions 17, 21 and 24 which are thought to increase calcium binding strength, improving mechanical properties of the bone matrix. Recent studies revealed that OCN exerts also i...

An increasing number of proteins are being shown to have an N -carboxylated lysine in their structures, a posttranslational modification of proteins that proceeds without the intervention of a specific enzyme. The role of the carboxylated lysine in theseproteins is typically structural (hydrogen bonding or metal coordination). However, carboxylated lysines in the active sites of OXA-10 and OXA-...

Graphene, the starting material for all the carbon nanostructures has attracted strong scientific and technological interest in recent years. It has shown great promise in many applications, such as electronics, energy storage and conversion (super capacitors, batteries, fuel cells, solar cells, and bioscience/biotechnologies. Graphene is a zero-gap semiconductor material, which is electroactiv...

Vitamin K is a substrate for the enzyme catalyzing the carboxylation of specific glutamyl residues to y-carboxyglutamy1 residues in hepatic precursors of a limited number of plasma proteins, including prothrombin. The y-carboxylation of these proteins can be blocked by the anticoagulant warfarin; and in the bovine and human, warfarin treatment results in the secretion of under-y-carboxylated fo...

We report on a 'green' method for the utilization of carbon dioxide as C1 unit for the regioselective synthesis of (E)-cinnamic acids via regioselective enzymatic carboxylation of para-hydroxystyrenes. Phenolic acid decarboxylases from bacterial sources catalyzed the β-carboxylation of para-hydroxystyrene derivatives with excellent regio- and (E/Z)-stereoselectivity by exclusively acting at the...

The carboxylation of olefins beyond ethylene towards α,β-unsaturated carboxylic acid salts and a detailed investigation on the critical steps in the catalysis are reported. The influence of two chelating phosphine ligands and several olefins on the elemental steps of the catalysis is shown. The work focusses on the formation of intermediate olefin complexes, lactone formation and base induced e...

Globular aggregates of carbon nanohorns (CNHs) often contain graphite-like thin sheets (GLSs), and providing different functions to CNHs and GLSs would expand the possible applications of the CNH-GLS aggregates. We show that the GLS edges can be carboxylated selectively by immersing the aggregates in an aqueous solution of H2O2 at room temperature for 1 hour. The presence of carboxyl groups was...