The Role of Sulphydryl Groups in Efflux of Taurine and Gaba from Cerebral Cortical Cells

1996 ◽  
pp. 409-416 ◽  
Author(s):  
Emma L. Upton ◽  
R. O. Law
Keyword(s):  
Cortical Cells ◽  
Sulphydryl Groups

Dissociation of FAD from the NAD(P)H-Nitrate Reductase Complex from Ankistrodesmus braunii and Role of Flavin in Catalysis

1982 ◽  
Vol 37 (1-2) ◽  
pp. 24-30 ◽  
Author(s):  
Miguel A. De la Rosa ◽  
Antonio J. Márquez ◽  
José M. Vega
Keyword(s):  
Nitrate Reductase ◽  
Reductase Activity ◽  
Prosthetic Group ◽  
Original Activity ◽  
Enzyme Preparations ◽  
Fluorescence Studies ◽  
Transport Chain ◽  
Sulphydryl Groups ◽  
Nadh Cytochrome

Ankistrodesmus braunii NAD(P)H-nitrate reductase is a complex hemoflavomolybdoprotein composed by eight similar subunits. The flavin prosthetic group, identified as FAD, is essential for the NAD(P)H-dependent activities of the complex, and is located before the heme chromo- phore in the enzyme electron transport chain from reduced pyridine nucleotides to nitrate. Fluorescence studies indicate that nitrate reductase can dissociate about 80% of its FAD by incubation at room temperature, the flavin dissociation being followed by a parallel decrease of NADH-nitrate reductase activity. Dissociation of FAD from the protein is easily increased by dilution or prolonged dialysis of the enzyme preparations. However, exogenous FAD specifically prevents the dissociation of enzyme-bound flavin, and protects the NAD(P)H-dependent activities. The Km for FAD, as a protector of NADH-cytochrome c reductase activity, is 4 nᴍ. In addition, dithioerythritol also prevents the flavin dissociation, and therefore the presence of free sulphydryl groups in the FAD-domain is suggested. FAD-depleted nitrate reductase, obtained by several methods, is unable to recover its original activity when incubated in the presence of FAD alone or with thiols.

scholarly journals The Role of the Sulphydryl Groups of Spleen Deoxycytidylate Aminohydrolase

1974 ◽  
Vol 46 (2) ◽  
pp. 401-405 ◽  
Author(s):  
Felice CERVONE ◽  
Carlo VACCARO ◽  
Santo SEPE ◽  
Eduardo SCARANO ◽  
Mose ROSSI
Keyword(s):  
Sulphydryl Groups

EFFECTS OF CORTICOSTERONE ON ADRENOCORTICOTROPHIN-INDUCED MITOCHONDRIAL DIFFERENTIATION WITH SPECIAL REFERENCE TO 11β-AND 18-HYDROXYLATION

1976 ◽  
Vol 70 (2) ◽  
pp. 215-222 ◽  
Author(s):  
M. SALMENPERÄ ◽  
A. I. KAHRI ◽  
A. SAURE
Keyword(s):  
Significant Inhibition ◽  
Dibutyryl Cyclic Amp ◽  
Adrenocortical Cells ◽  
Cortical Cells ◽  
Foetal Rat ◽  
Rat Adrenals ◽  
Induced Changes ◽  
Regulation Of Growth ◽  
Venous Plasma

SUMMARY The effects of corticosterone in concentrations found in adrenal venous plasma on ACTH-induced changes in cultured cortical cells derived from foetal rat adrenals were studied. Corticosterone at a concentration of 5·7 × 10−5 mol/l completely inhibited mitochondrial differentiation to fasciculate-like morphology. The same cultures revealed significant inhibition of 11β- and 18-hydroxylation compared with cultures treated with ACTH only. This was shown by the reduced formation of corticosterone and 18-OH-deoxycorticosterone (48%, P < 0·001) and simultaneous enhancement of deoxycorticosterone formation (33%, P < 0·05) from added [4-14C]progesterone. Similar inhibition was observed when dibutyryl cyclic AMP replaced ACTH as an inducer of differentiation. Lower concentrations of corticosterone (1·2 × 10−5 and 2·4 × 10−5 mol/l) inhibited ACTH-stimulated formation of corticosterone and 18-OH-deoxycorticosterone from endogenous precursors. The results demonstrate that corticosterone regulates the stage of differentiation in cultured adrenocortical cells. The possible role of corticosterone in the regulation of growth and steroidogenic capacity of the adrenal cortex is discussed.

scholarly journals A Dual-Targeted Soybean Protein Is Involved in Bradyrhizobium japonicum Infection of Soybean Root Hair and Cortical Cells

2011 ◽  
Vol 24 (9) ◽  
pp. 1051-1060 ◽  
Author(s):  
Marc Libault ◽  
Manjula Govindarajulu ◽  
R. Howard Berg ◽  
Yee Tsuey Ong ◽  
Kari Puricelli ◽  
...  
Keyword(s):  
Bradyrhizobium Japonicum ◽  
Soybean Protein ◽  
Carbon Utilization ◽  
Plant Host ◽  
Cortical Cells ◽  
Symbiotic Interaction ◽  
Carbon Supply ◽  
Glycine Max L ◽  
Soybean Gene

The symbiotic interaction between legumes and soil bacteria (e.g., soybean [Glycine max L.] and Bradyrhizobium japonicum]) leads to the development of a new root organ, the nodule, where bacteria differentiate into bacteroids that fix atmospheric nitrogen for assimilation by the plant host. In exchange, the host plant provides a steady carbon supply to the bacteroids. This carbon can be stored within the bacteroids in the form of poly-3-hydroxybutyrate granules. The formation of this symbiosis requires communication between both partners to regulate the balance between nitrogen fixation and carbon utilization. In the present study, we describe the soybean gene GmNMNa that is specifically expressed during the infection of soybean cells by B. japonicum. GmNMNa encodes a protein of unknown function. The GmNMNa protein was localized to the nucleolus and also to the mitochondria. Silencing of GmNMNa expression resulted in reduced nodulation, a reduction in the number of bacteroids per infected cell in the nodule, and a clear reduction in the accumulation of poly-3-hydroxybutyrate in the bacteroids. Our results highlight the role of the soybean GmNMNa gene in regulating symbiotic bacterial infection, potentially through the regulation of the accumulation of carbon reserves.

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