5 -Deoxy-5 -methylthioadenosine

Adenine phosphoribosyltransferase catalyzes the conversion of adenine to AMP in many tissues, by a reaction similar to that of hypoxanthine-guanine phosphoribosyltransferase, but is quite distinct from the latter. It plays a minor role in purine salvage since adenine is not a significant product of purine nucleotide catabolism (see below). The function of this enzyme seems to be to scavenge small amounts of adenine that are produced during intestinal digestion of nucleic acids or in the metabolism of 5 -deoxy-5 -methylthioadenosine, a product of polyamine synthesis. 

Ghoda, L. Y., Savarese, T. M. and North up, C. H. et al. (1988) Substrate specificities of 5 -deoxy-5 -methylthioadenosine phosphorylase from Trypanosoma brucei brucei and mammalian cells. Mol. Biochem. Parasitol. 27 109-118. 

The levels of 13 urinary nucleosides (e.g., dihydrouridine, pseudouridine, 1-methyladenosine, inosine, guanosine, 5 -deoxy-5 -methylthioadenosine) were monitored at 260 nm and 280 nm using a 30°C column and a 40-min 100/0 40/60... 

Porcelli, M., Cacciapuoti, G., Cimino, G., Gavagnin, M., Sodano, G., and Zappia, V., Biosynthesis and metabolism of 9-[5 deoxy-5 -(methylthio)-P-D-xylofuranosyl]adenine, a novel natural analogue of methylthioadenosine, Biochem. J., 263, 635, 1989. 

Enzymatic condensation of the thiol group of homo-L-cysteine with 05 of formycin (386) gave 476, which was 5-methylated and subsequently hydrolyzed to 5 -deoxy-5 -methylmercaptoformycin 477. Compound 477 potently inhibited rat liver 5 -methylthioadenosine phosphorylase (83MI4) (Scheme 129). 

When 2, 3 -dl-0-acetyl-5 -deoxy-5 -aryl(alkyl)sulphinyladenoslnes were treated with DAST and catal3rtic SbCla, followed by deacylatlon, novel fluorothionucleosides of type (33) were produced. These compounds, rather unstable for the case R=Me, were designed as potential inhibitors of S-adenosylhomocysteine and methylthioadenosine metabolism.78 The adenosine derivative (34) has been prepared in connection with studies of enzyme inhibition. 79... 

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