|Detection of Human, Mouse, and Rat NADK by Western Blot. Western blot shows lysates of HeLa human cervical epithelial carcinoma cell line, C2C12 mouse myoblast cell line, and NR8383 rat alveolar macrophage cell line. PVDF membrane was probed with 2 µg/mL of Sheep Anti-Human/Mouse/Rat NADK Antigen Affinity-purified Polyclonal Antibody (Catalog # AF8009) followed by HRP-conjugated Anti-Sheep IgG Secondary Antibody (Catalog # HAF016). A specific band was detected for NADK at approximately 50-55 kDa (as indicated). This experiment was conducted under reducing conditions and using Immunoblot Buffer Group 1.|
NADK (Nicotinamide Adenine Dinucleotide Kinase; also Poly(P)/ATP NAD kinase) is a 49-52 kDa cytosolic member of the NAD kinase family of enzymes. Although it is widely expressed, it is not found in skeletal muscle. NADK forms homotetramers and catalyzes the generation of NADP from NAD through the hydrolysis of ATP. NADP plays a role in fatty acid synthesis plus steroidogenesis, and provides a substrate for the generation of NADPH that serves to regulate the expression of reductases and antioxidant proteins. Human NADK is 446 amino acids (aa) in length. It contains one kinase domain (aa 105-429) plus a C-terminal Ala- and Glu-rich segment. There are four utilized phosphorylation sites at Ser46, Ser48, Ser50 and Ser64. The potential exists for an alternate start site at Met134, and two isoform variants are reported, one that contain a 56 aa substitution for aa 1-88, and another that possesses a 105 aa substitution for Met88 coupled to a 41 aa insertion after Glu131. Full-length NADK (aa 1-446) shares 91% aa sequence identity with mouse NADK. Recently, a human mitochondrial NADK was identified (termed C5orf33), but found to share only 19% aa sequence identity with cytosolic NADK.