title: Enzymology of NAD+ homeostasis in man.
abstract: This review describes the enzymes involved in human pyridine nucleotide metabolism starting with a detailed consideration of their major kinetic, molecular and structural properties. The presentation encompasses all the reactions starting from the de novo pyridine ring formation and leading to nicotinamide adenine dinucleotide (NAD(+)) synthesis and utilization. The regulation of NAD(+) homeostasis with respect to the physiological role played by the enzymes both utilizing NAD(+) through the nonredox NAD(+)-dependent reactions and catalyzing the recycling of the common product, nicotinamide, is discussed. The salient features of other enzymes such as NAD(+) pyrophosphatase, nicotinamide mononucleotide 5'-nucleotidase, nicotinamide riboside kinase and nicotinamide riboside phosphorylase, described under 'miscellaneous', are likewise presented.
authors.affiliation: Istituto di Biotecnologie Biochimiche, Università Politecnica delle Marche, Via Ranieri 69, 60131, Ancona, Italy. magnig@univpm.it
authors.forename: G
authors.initials: G
authors.lastname: Magni
authors.forename: A
authors.initials: A
authors.lastname: Amici
authors.forename: M
authors.initials: M
authors.lastname: Emanuelli
authors.forename: G
authors.initials: G
authors.lastname: Orsomando
authors.forename: N
authors.initials: N
authors.lastname: Raffaelli
authors.forename: S
authors.initials: S
authors.lastname: Ruggieri
mesh_terms: D004798:Enzymes / Q000378:metabolism*; D006706:Homeostasis; D006801:Humans; D006867:Hydrolases / Q000378:metabolism; D007700:Kinetics; D008954:Models, Biological; D009243:NAD / Q000378:metabolism*; D009612:Nicotinamide-Nucleotide Adenylyltransferase / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation
chemical_list: D004798:Enzymes; D009243:NAD; D009612:Nicotinamide-Nucleotide Adenylyltransferase; D006867:Hydrolases; C021480:kynureninase