Inosine phosphate

On silylation-amination of the disodium salts of inosine-5 -phosphate 238a or of guanosine-5 -phosphate 238 b with benzylamine, the phosphate moieties are also transiently protected during amination by silylation (cf also the silylation of uridine-5 -phosphate 224) to give, after transsilylation with methanol and addition of NaOH, the desired sodium salt of N -benzyladenosine-5 -phosphate 239a in 80% yield and the sodium salt of the 2-amino derivative 239 b in 78% yield [64] (Scheme 4.23). 

C23H32N10O16P2Pt2--0.4 CioHnN408P2- 2.4 Na+-13.8 HzO Sodium (trimethylenediamine)bis(inosine 5 -phosphato)platinum(II) inosine 5 -phosphate, hydrate (INOSPU)347... 

C10H21N4NiO13P-2 H20 Penta-aquo-nickel(H)-inosine 5 -phosphate, dihydrate ANIMPH, 01 32 381... 

C20H28N 10O16P2Pt2- 0.88 hydrate Sodium diammine-platinum-(inosine 5 -phosphate)-inosine SINPPT 34 375... 

C10HuN4OsPs, 2.88 Na+16 HjO 0.86 C20H28N10O16P2Pt2-0.28 5 -phosphate, hexadecahydrate Sodium diammine-bis(inosine 5 -phosphate)-platinum(n)- IMPPTS 43 308... 

C10H12N4O8P- -2 Na+16 H20 Li 2 H20 (inosine 5 -phosphate), hexadecahydrate Lithium (5 -nicotinamido-D-ribosyl)-(5 -adenyl)diphosphate, NADLIH 38 527... 

The amino group now provides the nucleus for purine ring formation, an extended series of reactions we shall not describe. The first-formed purine product is inosine 5 -phosphate (IMP), which leads to either AMP or GMP these require amination at alternative sites, and utilize either GTP- or ATP-dependent reactions for amination. GTP or ATP (as appropriate) will also be required for further phosphorylations to produce the nucleotide triphosphates. 

In the body, mercaptopurine is converted into an active form of the drug, nucleotide 6-thioinosin-5-phosphate. Nucleotide 6-thioinosin-5-phosphate inhibits the first step in the synthesis of inosin-5-phosphate by negative feedback, preventing its transformation to adenosine or guanine nucleotides, which are necessary for synthesizing DNA. Thus,... 

Disodium inosine 5 -phosphate C-2 endo (two independent molecules) 90... 

Scheme 5 Biosynthesis of inosine 5 -phosphate the nature of the Cj donors is described in the text (P = P03H2)...

Figure 25-16 Control of the conversion of inosine 5 -phosphate to the adenine and guanine ribonucleotides and deoxyribonucleotides in bacteria by feedback inhibition and activation.

L3. Lieberman, I., Involvement of guanosine triphosphate in the synthesis of adenylosuccinate from inosine-5 -phosphate. /. Am. Chem. Soc. 78, 251 (1956). 

Extracts of Aerobacter aerogenes (the wild, the purine-less mutant, and the guanine-less mutant), as well as a guanine-less mutant of Salmonella typhimurium which accumulates xanthosine in its culture medium, have been shown to contain an enzyme which catalyzes the oxidation of inosine 5-phosphate (XXVIII) to xanthosine 5-phosphate (XXIX). 

Inosine 5-phosphate (XXX) was converted to adenylosuccinate [6-(succinylamino)-9-(5-0-phospho-/8-D-ribofuranosyl)purine, XXXI] which was isolated by ion-exchange chromatography and was identified by analysis and by its characteristic absorption spectrum. The stoichiometry of the reaction was also verified by isolation and determination of the reactants. Hydroxylamine could replace L-aspartate, and the product formed was isolated and tentatively identified as iV -hydroxyadenosine 5-phosphate. A crude extract of Escherichia coli B was shown to split adenylosuccinate to adenosine 5-phosphate and fumaric acid. 

H-< Imidazolo 4,5-e -tetrazolo[ 1,5-a -pyrimidin) 8-Hydroxy-5-(5-phospho-/ -D-ribofuranosyl)-E9b/2, 537 (2-C1 —inosin — 5 -phosphat + NaN3)... 

DISODIUM INOSINE-5 -PHOSPHATE IMP DISODIUM SALT 5 -IMP DISODIUM SALT IMP SODIUM SALT INOSINE-5 -MONOPHOSPHATE DISODIUM INOSIN-5 -iMONOPHOSPHATE DISODIUM SODIUM INOSINATE SODIUM-5 -INOSINATE... 

DISODIUM INOSINE-5 -PHOSPHATE see DXE500 DISODIUM METASIUCATE see SJUOOO DISODIUM MOLYBDATE see DXE800 DISODIUM MONOHYDROGEN ARSENATE see... 

The substrates most generally used in measuring the activity of NTP are AMP or IMP (inosine-5"-phosphate). However, these substrates are organic phosphate esters and thus can be hydrolyzed to an appreciable degree by other nonspecific (alkaline) phosphatases, even at a pH as low as 7.5, which is the pH assumed optimal for NTP activity. Methods for the estimation of NTP in serum must therefore incorporate some means for correcting for the hydrolysis of the substrate by the nonspecific phosphatases. 

GIS. Greenberg, G. R., De novo synthesis of hypoxanthine via inosine-5-phosphate and inosine. J. Biol. Chem. 190, 611-631 (1951). 

M2. Magasanik, B., Moyed, H. S., and Gehring, L. B., Enzymes essential for the biosynthesis of nucleic acid guanine inosine 5 -phosphate dehydrogenase of Aerobacler aerogenes. J. Biol. Chem. 226, 339-350 (1957). 

---