Photosynthetic efficiency is a critical determinant of crop yield potential, although it remains below the theoretical optimum in modern crop varieties. Enhancing mesophyll conductance (i.e. the rate of carbon dioxide diffusion from substomatal cavities to the sites of carboxylation) may increase photosynthetic and water use efficiencies. To improve water use efficiency, mesophyll conductance s...

The objective of this study was to test the effect of increasing fatty acid concentrations on substrate fluxes through pathways leading to citrate synthesis and release in the heart. This was accomplished using semirecirculating work-performing rat hearts perfused with substrate mixtures mimicking the in situ milieu (5.5 mM glucose, 8 nM insulin, 1 mM lactate, 0.2 mM pyruvate, and 0.4 mM oleate...

If gamma-carboxylation, by the vitamin K1 - cycle, of glutamate residues of bone-matrix peptides is essential for the formation of bone, the circulating levels of this vitamin might indicate the potential efficiency of this process. Methods involving HPLC with electrochemical detection have very recently been developed for assaying the low levels of vitamin K1 that occur in normal plasma. Using...

The bacterial metabolism of propylene proceeds by epoxidation to epoxypropane followed by a sequence of three reactions resulting in epoxide ring opening and carboxylation to form acetoacetate. Coenzyme M (2-mercaptoethanesulfonic acid) (CoM) plays a central role in epoxide carboxylation by serving as the nucleophile for epoxide ring opening and the carrier of the C(3) unit that is ultimately c...

Plants with crassulacean acid metabolism (CAM) are increasing their abundance in drylands worldwide. The drivers and mechanisms underlying the increased dominance of CAM plants and CAM expression (i.e., nocturnal carboxylation) in facultative CAM plants, however, remain poorly understood. We investigated how nutrient and water availability affected competition between Mesembryanthemum crystalli...

Malic enzyme catalyzes the reversible oxidative decarboxylation of malate to pyruvate and CO(2). The Saccharomyces cerevisiae MAE1 gene encodes a mitochondrial malic enzyme whose proposed physiological roles are related to the oxidative, malate-decarboxylating reaction. Hitherto, the inability of pyruvate carboxylase-negative (Pyc(-)) S. cerevisiae strains to grow on glucose suggested that Mae1...