NAD Kinase (NADK)

NAD+ kinase (EC 2.7.1.23, NADK) is an enzyme that converts nicotinamide adenine dinucleotide (NAD+) into NADP+, through phosphorylating the NAD+ coenzyme. NADP+ is an essential coenzyme in metabolism and provides reducing power to biosynthetic processes such as fatty acid biosynthesis. The structure of the NADK from the archaean Archaeoglobus fulgidus has been determined.The deduced 446-amino acid protein has a calculated molecular mass of 49.2 kD. Northern blot analysis detected a 3.0-kb transcript with high expression in placenta, moderate expression in brain, colon, heart, liver, kidney, lung, spleen, stomach, and testis, and low expression in small intestine. A band of 1.8 kb was detected in several tissues.