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Full-Text Articles in Biotechnology
In Vivo Regulatory Phosphorylation Site In C4-Leaf Phosphoenolpyruvate Carboxylase From Maize And Sorghum, Jin-An Jiao, Jean Vidal, Cristina Echevarría, Raymond Chollet
In Vivo Regulatory Phosphorylation Site In C4-Leaf Phosphoenolpyruvate Carboxylase From Maize And Sorghum, Jin-An Jiao, Jean Vidal, Cristina Echevarría, Raymond Chollet
Department of Biochemistry: Faculty Publications
Reversible seryl-phosphorylation contributes to the light/dark regulation of C4-leaf phosphoenolpyruvate carboxylase (PEPC) activity in vivo. The specific regulatory residue that, upon in vitro phosphorylation by a maize-leaf protein-serine kinase(s), leads to an increase in catalytic activity and a decrease in malatesensitivity of the target enzyme has been recently identified as Ser-15 in 32P-phosphorylated/activated dark-form maize PEPC (J-A Jiao, R Chollet [1990] Arch Biochem Biophys 283: 300-305). In order to ascertain whether this N-terminal seryl residue is, indeed, the in vivo regulatory phosphorylation site, [32P]phosphopeptides were isolated and purified from in vivo 32P-labeled maize and …
Purification And Characterization Of Soybean Root Nodule Ferric Leghemoglobin Reductase, Lin Ji, Stephen Wood, Manuel Becana, Robert V. Klucas
Purification And Characterization Of Soybean Root Nodule Ferric Leghemoglobin Reductase, Lin Ji, Stephen Wood, Manuel Becana, Robert V. Klucas
Department of Biochemistry: Faculty Publications
A ferric leghemoglobin reductase from the cytosol of soybean (Glyclne max) root nodules was purified to homogeneity and partlafly characterized. The enzyme is a flavoprotein with flavin adenine dinuclotide as the prosthetic group and consists of two identical subunits, each having a molecular mass of 54 kilodaltons. The pure enzyme shows a high activity for ferric leghemoglobin reduction with NADH as the reductant in the absence of any exogenous mediators. The enzyme also exhibits NADH-dependent 2,6-dichloroindophenol reductase activity. A sequence of the first 50 N-terminal amino acids of the purified protein was obtained. Comparisons with known protein sequences …
Posttranslational Regulation Of Phosphoenolpyruvate Carboxylase In C4 And Crassulacean Acid Metabolism Plants, Jin-An Jiao, Raymond Chollet
Posttranslational Regulation Of Phosphoenolpyruvate Carboxylase In C4 And Crassulacean Acid Metabolism Plants, Jin-An Jiao, Raymond Chollet
Department of Biochemistry: Faculty Publications
Control of C4 photosynthesis and Crassulacean acid metabolism (CAM) is, in part, mediated by the diel regulation of phosphoenolpyruvate carboxylase (PEPC) activity. The nature of this regulation of PEPC in the leaf cell cytoplasm of C4 and CAM plants is both metabolite-related and posttranslational. Specifically, the regulatory properties of the enzyme vary in accord with the physiological activity of C4 photosynthesis and CAM: PEPC is less sensitive to feedback inhibition by L-malate under light (C4 plants) or at night (CAM plants) than in darkness (C4) or during the day (CAM). While the view that …
Nicotinate, Nicotinamide, And The Reactivity Of Leghemoglobin In Soybean Root Nodules, Robert V. Klucas, Cyril A. Appleby
Nicotinate, Nicotinamide, And The Reactivity Of Leghemoglobin In Soybean Root Nodules, Robert V. Klucas, Cyril A. Appleby
Department of Biochemistry: Faculty Publications
Nicotinate has been postulated to interfere with the binding of O2 to ferrous leghemoglobin in soybean (Glycine max) root nodules. For such a function, the levels of nicotinate in nodules must be sufficiently high to bind a significant amount of leghemoglobin. We have measured levels of nicotinate, nicotinamide, and leghemoglobin in soybean nodules from plants 34 to 73 days after planting in a glasshouse. On a per gram nodule fresh weight basis, levels between 10.4 and 21 nanomoles for nicotinate, 19.2 and 37.8 nanomoles for nicotinamide, and 170 to 280 nanomoles for leghemoglobin were measured. Even if …