Characterization of recombinant human nicotinamide mononucleotide adenylyl transferase (NMNAT), a nuclear enzyme essential for NAD synthesis

FEBS Letters

Hennig, Klaus¹  Schweiger, Manfred¹  Oei, Shiao Li¹  Weise, Christoph¹  Niere, Marc¹  Specht, Thomas¹  Ziegler, Mathias¹  Lerner, Felicitas¹  Hirsch-Kauffmann, Monica¹ 

[1] Institut für Biochemie, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany

关键词: Nicotinamide mononucleotide adenylyl transferase;    NMNAT;    NAD synthesis;    MALDI-TOF;    matrix-assisted laser desorption/ionization-time of flight;    NMNAT;    nicotinamide mononucleotide adenylyl transferase;    PARP1;    poly(ADP-ribose) polymerase 1;    SDS–PAGE;    sodium dodecyl sulfate–polyacrylamide gel electrophoresis;   

DOI  :  10.1016/S0014-5793(01)02180-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Nicotinamide mononucleotide adenylyl transferase (NMNAT) is an essential enzyme in all organisms, because it catalyzes a key step of NAD synthesis. However, little is known about the structure and regulation of this enzyme. In this study we established the primary structure of human NMNAT. The human sequence represents the first report of the primary structure of this enzyme for an organism higher than yeast. The enzyme was purified from human placenta and internal peptide sequences determined. Analysis of human DNA sequence data then permitted the cloning of a cDNA encoding this enzyme. Recombinant NMNAT exhibited catalytic properties similar to the originally purified enzyme. Human NMNAT (molecular weight 31 932) consists of 279 amino acids and exhibits substantial structural differences to the enzymes from lower organisms. A putative nuclear localization signal was confirmed by immunofluorescence studies. NMNAT strongly inhibited recombinant human poly(ADP-ribose) polymerase 1, however, NMNAT was not modified by poly(ADP-ribose). NMNAT appears to be a substrate of nuclear kinases and contains at least three potential phosphorylation sites. Endogenous and recombinant NMNAT were phosphorylated in nuclear extracts in the presence of [γ-³²P]ATP. We propose that NMNAT's activity or interaction with nuclear proteins are likely to be modulated by phosphorylation.

【 授权许可】

Unknown