Update of the BIPM comparison BIPM.RI(II)-K1.Cs-134 of activity measurements of the radionuclide 134Cs to include the 2008 results of the BEV (Austria), the 2009 result of the IRA (Switzerland) and the 2010 results of the NMISA (South Africa)

Détails

ID Serval
serval:BIB_1B88920FE316
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Update of the BIPM comparison BIPM.RI(II)-K1.Cs-134 of activity measurements of the radionuclide 134Cs to include the 2008 results of the BEV (Austria), the 2009 result of the IRA (Switzerland) and the 2010 results of the NMISA (South Africa)
Périodique
Metrologia
Auteur⸱e⸱s
Michotte C., Ratel G., Courte S., Maringer F.J., Caffari Y., van Wyngaardt W.M.
ISSN
1681-7575 (Electronic)
ISSN-L
0006-2952
Statut éditorial
Publié
Date de publication
2013
Volume
50
Numéro
1A
Pages
06009
Langue
anglais
Résumé
Purine nucleotide pyrophosphotransferase was purified to apparent homogeneity from a culture filtrate of Streptomyces morookaensis. It is a monomeric protein with a molecular weight of 24 000-25 000, and its isoelectric point is 6.9. The enzyme synthesizes purine nucleoside 5'-phosphate (mono, di, or tri) 3'-diphosphates such as pppApp, ppApp, pApp, pppGpp, ppGpp and pppIpp by transferring a pyrophosphoryl group from the 5'-position of ATP, dATP and ppApp to the 3'-position of purine nucleotides. The purified enzyme catalysed the formation of 435 mumol of pppApp and 620 mumol of pppGpp from ATP and GTP per min mg protein under the standard conditions. The enzyme requires absolutely a divalent cation for activity, and optimum pH for the enzyme activity lay above 10 for Mg2+, for Co2+ and Zn2+ from 9 to 9.5, and for Fe2+ from 7.5 to 8. The following Michaelis constants were determined: AMP, 2.78 mM; ADP, 3.23 mM; GMP, 0.89 mM; GDP, 0.46 mM and GTP, 1.54 mM, in the case of ATP donor. The enzyme is inhibited by guanine, guanosine, dGDP, dGTP, N-bromosuccinimide, iodacetate, sodium borate and mercuric acetate.
Mots-clé
Animals, Chromatography, Thin Layer, Digitoxigenin/metabolism, Digitoxin/metabolism, Hydroxylation, Male, Microsomes, Liver/metabolism, NADP/metabolism, Rats, Time Factors
Web of science
Création de la notice
13/02/2014 9:52
Dernière modification de la notice
20/08/2019 12:52
Données d'usage