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Pyridine dinucleotide biosynthesis in archaebacteria: Presence of NMN adenylyltransferase in Sulfolobus solfataricus
Author(s) -
Raffaelli Nadia,
Amici Adolfo,
Emanuelli Monica,
Ruggieri Silverio,
Magni Giulio
Publication year - 1994
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(94)01195-8
Subject(s) - sulfolobus solfataricus , biochemistry , sulfolobus , thermophile , enzyme , nad+ kinase , isoelectric point , chemistry , biosynthesis , biology , archaea , gene
The enzyme NMN adenylyltransferase, leading to NAD synthesis, has been observed for the first time in soluble extracts from the extreme acidothermophilic archaeon Sulfolobus solfataricus . Comparison of its molecular and kinetic properties with those of the enzyme isolated from prokaryotes and eukaryotes revealed significant differences, knowledge of which may contribute to the understanding of metabolic evolutionary mechanisms. The thermophilic enzyme shows a molecular mass of about 66,000 and an isoelectric point of 5.4. The K m values for ATP, NMN and nicotinic acid mononucleotide are 0.08 μM, 1.4 μM and 17 μM, respectively. The enzyme shows a remarkable degree of thermophilicity, with an activation energy of 95 kJ/mol.