Regulation of a NAD + Kinase Activity Isolated from Asynchronous Cultures of the Achlorophyllous ZC Mutant of Euglena gracilis
| العنوان: | Regulation of a NAD + Kinase Activity Isolated from Asynchronous Cultures of the Achlorophyllous ZC Mutant of Euglena gracilis |
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| المؤلفون: | Goto K, Carré Ia, Pou de Crescenzo Ma, Laval-Martin Dl |
| المصدر: | Zeitschrift für Naturforschung C. 52:623-635 |
| بيانات النشر: | Walter de Gruyter GmbH, 1997. |
| سنة النشر: | 1997 |
| مصطلحات موضوعية: | Chlorophyll, NAD+ kinase activity, Euglena gracilis, Kinase, ved/biology, Effector, ved/biology.organism_classification_rank.species, Mutant, Biology, NAD, Molecular biology, General Biochemistry, Genetics and Molecular Biology, Circadian Rhythm, Kinetics, Phosphotransferases (Alcohol Group Acceptor), EGTA, chemistry.chemical_compound, Biochemistry, chemistry, Chromatography, Gel, Animals, NAD+ kinase, Binding site, NADP |
| الوصف: | NAD+ kinase was isolated by chromatography steps from asynchronous cultures of the achlorophyllous ZC mutant of Euglena gracilis. A non Ca2+-calmodulin dependent form, whose activity was stimulated by EGTA, was selected for its large quantity and high specific activity. Studies of the kinetic parameters revealed two kinds of NAD+ binding site, depending on NAD+ concentrations, and changes induced by EGTA, Ca2+ and Ca2+-calmodulin. The search for effectors, soluble (S) and membrane-bound (P), in Euglena gracilis synchronously grown (in a light-dark regime of 12h:12h), and collected at circadian times (CT) - corresponding to the maximum, CT 17, and to the trough, CT 09, of the circadian rhythm of NAD+ kinase activity - was also undertaken by testing the modulations of the kinetic parameters of the prepared NAD+ kinase. The results suggest: (i) structural changes of NAD+ binding sites depending on NAD+ concentrations; (ii) possible binding of the Mg-ATP-2 (or Ca-ATP-2) on the NAD+ sites, because of their common ADP motif; and (iii) different and specific modulations of the kinetic parameters of the two types of NAD+ binding site by the Ca2+-calmodulin complex. In addition, the results indicate, in pelletable fractions isolated at CT 09 and CT 17, the presence of two kinds of effector: (i) the first one, possibly Ca2+, which increases the Umax’s while decreasing the binding of NAD+; (ii) the second one, possibly the Ca2+-calmodulin complex, which provokes a complete reverse effect. Each of these two effectors seems to be, alternatively and rhythmically (eight circadian hours apart), partially released from the membranes |
| تدمد: | 1865-7125 0939-5075 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::2db83d5bb3470f46ee9b530ee4d65262 https://doi.org/10.1515/znc-1997-9-1009 |
| حقوق: | OPEN |
| رقم الأكسشن: | edsair.doi.dedup.....2db83d5bb3470f46ee9b530ee4d65262 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 18657125 09395075 |
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