Identification of a novel human nicotinamide mononucleotide adenylyltransferase.
The enzyme nicotinamide mononucleotide adenylyltransferase is an ubiquitous enzyme catalyzing an essential step in NAD (NADP) biosynthetic pathway. In human cells, the nuclear enzyme, which we will now call NMNAT-1, has been the only known enzyme of this type for over 10 years. Here we describe the cloning and expression of a human cDNA encoding a novel 34.4kDa protein, that shares significant homology with the 31.9kDa NMNAT-1. We propose to call this enzyme NMNAT-2. Purified recombinant NMNAT-2 is endowed with NMN and nicotinic acid mononucleotide adenylyltransferase activities, but differs from NMNAT-1 with regard to chromosomal and cellular localization, tissue-specificity of expression, and molecular properties, supporting the idea that the two enzymes might play distinct physiological roles in NAD homeostasis.
D000595:Amino Acid Sequence; D001483:Base Sequence; D002467:Cell Nucleus / Q000201:enzymology*; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D017931:DNA Primers; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D009243:NAD / Q000096:biosynthesis; D009249:NADP / Q000096:biosynthesis; D009612:Nicotinamide-Nucleotide Adenylyltransferase / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D011994:Recombinant Proteins; D009243:NAD; D009249:NADP; D004247:DNA; C484007:NMNAT1 protein, human; C484008:NMNAT2 protein, human; C484009:NMNAT3 protein, human; D009612:Nicotinamide-Nucleotide Adenylyltransferase