• 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 ...

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 ...

There is a trade-off between nitrogen (N) allocation to photosynthesis and to defence. Invasive species may reduce N allocation to defence because of the absence of natural enemies. Thus, I hypothesised that invasive species may allocate a higher fraction of total leaf N to photosynthesis and have higher light-saturated photosynthetic rate (P(max)) and photosynthetic N-use efficiency (PNUE) tha...

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...

Comparative kinetic studies at pH 6.8, 7.3, and 8.0 reveal that the phosphoenolpyruvate carboxykinase-catalyzed inosine trlphosphate-dependent oxalacetate-H14C0sexchange is much more rapid than either the over-all decarboxylation or carboxylation reactions. At pH 6.8, the relative carboxylation, decarboxylation, and oxalacetate-H14C03exchange rates are 1.0, 8.3, and 30, respectively. While the ...

Anaplerotic pyruvate carboxylation was examined in hearts perfused with physiological concentrations of glucose, [U-13C3]lactate, and [U-13C3]pyruvate. Also, a fatty acid, [1-13C]octanoate, or ketone bodies were added at concentrations providing acetyl-CoA at a rate resulting in either low or substantial pyruvate decarboxylation. Relative contributions of pyruvate and fatty acids to citrate syn...

The anaerobic metabolism of phenol in the beta-proteobacterium Thauera aromatica proceeds via carboxylation to 4-hydroxybenzoate and is initiated by the ATP-dependent conversion of phenol to phenylphosphate. The subsequent para carboxylation of phenylphosphate to 4-hydroxybenzoate is catalyzed by phenylphosphate carboxylase, which was purified and studied. This enzyme consists of four proteins ...