The bacterial metabolism of short-chain aliphatic alkenes occurs via oxidation to epoxyalkanes followed by carboxylation to beta-ketoacids. Epoxyalkane carboxylation requires four enzymes (components I-IV), NADPH, NAD(+), and a previously unidentified nucleophilic thiol. In the present work, coenzyme M (2-mercaptoethanesulfonic acid), a compound previously found only in the methanogenic Archaea...

Recent studies have demonstrated that fumarate addition and carboxylation are two possible mechanisms of anaerobic alkane degradation. In the present study, we surveyed metabolites formed during growth on hexadecane by the sulfate-reducing isolates AK-01 and Hxd3 and by a mixed sulfate-reducing consortium. The cultures were incubated with either protonated or fully deuterated hexadecane; the su...

In the well-perfused heart, pyruvate carboxylation accounts for 3-6% of the citric acid cycle (CAC) flux, and CAC carbon is lost via citrate release. We investigated the effects of an acute reduction in coronary flow on these processes and on the tissue content of CAC intermediates. Measurements were made in an open-chest anesthetized swine model. Left anterior descending coronary artery blood ...

• Factor IX glutamyl carboxylation in engineered HEK 293 cells recapitulates in vivo anticoagulant inhibition of vitamin K cycle activity. • Warfarin metabolite structureactivity analysis on vitamin K cycle antagonism determines their contributions to in vivo anticoagulation. Warfarin and other 4-hydroxycoumarins inhibit vitamin K epoxide reductase (VKOR) by depleting reduced vitamin K that is ...

ABSTRACT The objective of this study was to evaluate the effects different combinations nitrogen and potassium fertilization on gas exchange chlorophyll a fluorescence in seedlings guava cv. Paluma irrigated with water salinity levels. experiment set up randomized block design analyzed 5 × 4 factorial scheme, four replicates. treatments were composed combination factor electrical conductivity i...

Considering the major role of insulin signaling on fatty acid synthesis via stimulation of lipogenic enzymes, differential effects of insulin signaling on individual carbon fluxes for fatty acid synthesis have been investigated by comparing the individual lipogenic fluxes in WT and IRS-1 knockout (IRS-1 KO) brown adipocytes. Results from experiments on WT and IRS-1 KO cells incubated with [5C] ...

Warfarin and other 4-hydroxycoumarins inhibit vitamin K epoxide reductase (VKOR) by depleting reduced vitamin K that is required for posttranslational modification of vitamin K-dependent clotting factors. In vitro prediction of the in vivo potency of vitamin K antagonists is complicated by the complex multicomponent nature of the vitamin K cycle. Here we describe a sensitive assay that enables ...

Osteocalcin (OCN) is an osteoblast-derived hormone favoring glucose homeostasis, energy expenditure, male fertility, brain development, and cognition. Before being secreted by osteoblasts in the bone extracellular matrix, OCN is γ-carboxylated by the γ-carboxylase (GGCX) on three glutamic acid residues, a cellular process requiring reduction of vitamin K (VK) by a second enzyme, a reductase cal...

A model is presented which enables gas exchange data to be used to partition the intracellular resistance to leaf photosynthesis into carboxylation and transport components. A basic assumption is that the over-all kinetics of the carboxylation reaction fit the Michaelis-Menten equation.The model was tested for cotton (Gossypium hirsutum L., var. Deltapine Smoothleaf), where photorespiration was...