title: Nicotinamide 3,N4-ethenocytosine dinucleotide, an analog of nicotinamide adenine dinucleotide. Synthesis and enzyme studies.
abstract: A structural analog of NAD+, NICOTINAMIDE 3,N-4ethenocytosine dinucleotide (epsilonNCD+), has been synthesized, characterized, and compared in activity with the natural coenzyme in several enzyme systems. The Vmax and apparent Km values were determined for NAD+, epsilonNCD+, and epsilonNAD+ (nicotinamide 1, N6-ethenoadenine dinucleotide) with yeast alcohol, horse liver alcohol, pig heart malate, beef liver glutamate, and rabbit muscle lactate and glyceraldehyde-3-phosphate dehydrogenases. The Vmax for epsilonNCD+ was as great or greater than that obtained for NAD+ with three of the enzymes, 60-80 per cent with two others, and 14 percent with one. EpsilonNCD+ was found to be more active than epsilonNAD+ with all six dehydrogenases. EpsilonNCD+ served as a substrate for Neurospora crassa tnadase, but could not be phosphorylated with pigeon liver NAD+ kinase. NAD+ pyrophosphorylase from pig liver was unable to catalyze the formation of epsilonNCD+ from the triphosphate derivative of epsilon-cytidine and nicotinamide mononucleotide, but was able to slowly catalyze the pyrolytic cleavage of epsilonNCD+. The coenzyme activity of epsilonNCD+ with dehydrogenases can be discussed in terms of the close spatial homology of epsilonNCD+ and NAD+, which may allow similar accommodations within the enzyme binding regions.
mesh_terms: D000818:Animals; D002855:Chromatography, Thin Layer; D003596:Cytosine / Q000031:analogs & derivatives; D004590:Electrophoresis, Paper; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D009243:NAD / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism; D010770:Phosphotransferases / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013552:Swine
chemical_list: D009243:NAD; D003596:Cytosine; D010088:Oxidoreductases; D010770:Phosphotransferases