Dinucleotides, monophosphates, proton

Many extensive studies110-126 at 60, 100, or 220 MHz of dinucleotides and dinucleoside monophosphates have confirmed quite conclusively that the magnetic anisotropy of one base moiety influences the chemical shifts of the protons of the other base and, therefore, that these compounds exist in one or more folded conformations, in which the rings of the bases are stacked in parallel planes. Intra- and inter-molecular base-stacking both appear to be extremely common,103,122-126 and the chemical shifts experienced by H-l, H-2, and H-8 of adenylyl-(3 - 5 )-adenosine (44) on inter-... 

PH Decoupling of trialkyl phosphites and phosphates by paramagnetic reagents only occurs when there is direct co-ordination. In most cases 8p is shifted downfield, but h showed no definite trend. The most effective reagent was cobalt chloride in acetonitrile solution. The H-1 proton of dinucleotide mono- and di-phosphates was identified by the broadening of its resonance that occurred upon the addition of Mn + ions. A study of the effects of paramagnetic ions on adenosine 5 -monophosphate has also been reported. ... 

Figure 3.8. Structures of vitamins or vitamin-derived molecules that function in oxidation-reduction reactions. The oxidation of these redox groups in the inner mitochondricil membrane contributes to the electron transport chain that carries electrons from the oxidation of glucose to oxygen and in the process pumps protons from one side to the other of the inner mitochondrial membrane (see Chapter 8 for details). The proton gradient thus formed is used to phosphorylate ADP to form 32 of the 36 ATPs resulting from the oxidation of one glucose molecule to six CO2 and six H2O molecules. A Vitamin B3, also called niacin or nicotinic acid, becomes converted to the amide (nicotinamide) and dressed up with a ribose sugar. Then, in a manner like that of riboflavin in B becomes phosphorylated to form nicotinamide mononucleotide (NMN) or further reacted with the addition of adenosine monophosphate (AMP) to form nicotinamide adenine dinucleotide (NAD). B Vitamin B2, also known as riboflavin, is shown converted to the forms involved in redox reactions such as those of the electron transport chain. (From Biochemistry, Second Edition, D. Voet and J. Voet, Copyright 1995, John Wiley Sons, New York. Reprinted with permission of John Wiley Sons, Inc.)...

The dinucleotide NAD" (and NADH, NAD(P)", and NAD(P)H) is composed of ADP and a second ribosyl unit to which a nicotinamide is appended at the anomeric carbon. The biosynthesis of adenosine monophosphate (adenosine 5 -phosphate, AMP) was outlined above, and AMP can be converted to ADP by the action of adenylate kinase (EC 2.7.4.3). The enzymes called ATP synthases (EC 3.6.3.14 and 3.6.3.15) are complicated membrane- and nonmembrane-associated species that convert the energy associated with proton electrochemical gradients into ATP from ADP and inorganic phosphate (Pi) (Chapter 14). 

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