High impact information on NADK1

• Expressed as recombinant proteins in bacteria, both NADK1 and NADK2 were catalytically active, thereby confirming their identity as NADKs [1].
• NAD kinase (NADK; ATP:NAD 2'-phosphotransferase, EC 2.7.1.23), an enzyme found in both prokaryotes and eukaryotes, generates the important pyridine nucleotide NADP from substrates ATP and NAD [1].
• NAD kinase (NADK), the catalyzing enzyme for the de novo synthesis of NADP from substrates NAD and ATP, may play an important role in the synthesis of NADPH [2].
• NADK activity has been observed in different sub-cellular fractions of mitochondria, chloroplast, and cytoplasm [2].
• A novel Arabidopsis thaliana gene (AtNADK-1) was identified based on its response to radiation and oxidative stress [3].

Biological context of NADK1

• Although the predicted catalytic regions for NADK1 and NADK2 show sequence similarity to NADKs from other organisms, NADK2 possesses a large N-terminal extension that appears to be unique to plants [1].
• The full-length AtNADK-1 cDNA encodes a 58-kDa protein that shows high sequence homology to the recently defined family of NAD(H) kinases [3].
• Using reverse genetics, we demonstrate that AtNADK-1 deficient plants display enhanced sensitivity to gamma irradiation and to paraquat-induced oxidative stress [3].

References