TY - JOUR
T1 - Allosteric regulation of Bacillus subtilis NAD kinase by quinolinic acid
AU - Garavaglia, Silvia
AU - Galizzi, Alessandro
AU - Rizzi, Menico
PY - 2003/8
Y1 - 2003/8
N2 - NADP is essential for biosynthetic pathways, energy, and signal transduction. In living organisms, NADP biosynthesis proceeds through the phosphorylation of NAD with a reaction catalyzed by NAD kinase. We expressed, purified, and characterized Bacillus subtilis NAD kinase. This enzyme represents a new member of the inorganic polyphosphate [poly(P)]/ATP NAD kinase subfamily, as it can use poly(P), ATP, or other nucleoside triphosphates as phosphoryl donors. NAD kinase showed marked positive cooperativity for the substrates ATP and poly(P) and was inhibited by its product, NADP, suggesting that the enzyme plays a major regulatory role in NADP biosynthesis. We discovered that quinolinic acid, a central metabolite in NAD(P) biosynthesis, behaved like a strong allosteric activator for the enzyme. Therefore, we propose that NAD kinase is a key enzyme for both NADP metabolism and quinolinic acid metabolism.
AB - NADP is essential for biosynthetic pathways, energy, and signal transduction. In living organisms, NADP biosynthesis proceeds through the phosphorylation of NAD with a reaction catalyzed by NAD kinase. We expressed, purified, and characterized Bacillus subtilis NAD kinase. This enzyme represents a new member of the inorganic polyphosphate [poly(P)]/ATP NAD kinase subfamily, as it can use poly(P), ATP, or other nucleoside triphosphates as phosphoryl donors. NAD kinase showed marked positive cooperativity for the substrates ATP and poly(P) and was inhibited by its product, NADP, suggesting that the enzyme plays a major regulatory role in NADP biosynthesis. We discovered that quinolinic acid, a central metabolite in NAD(P) biosynthesis, behaved like a strong allosteric activator for the enzyme. Therefore, we propose that NAD kinase is a key enzyme for both NADP metabolism and quinolinic acid metabolism.
UR - http://www.scopus.com/inward/record.url?scp=0042060978&partnerID=8YFLogxK
U2 - 10.1128/JB.185.16.4844-4850.2003
DO - 10.1128/JB.185.16.4844-4850.2003
M3 - Article
SN - 0021-9193
VL - 185
SP - 4844
EP - 4850
JO - Journal of Bacteriology
JF - Journal of Bacteriology
IS - 16
ER -