Psicofuranine

Psicofuranine is an antibiotic that acts as an inhibitor of xanthosine 5’-phosphate (XMP) aminase with IC50 value of 67 μM [1][2][3].

Xanthosine 5’-phosphate (XMP) aminase is an enzyme essential for guanine nucleotide synthesis and possess catalytic activity with either glutamine or ammonia as a substrate [2][3].

Psicofuranine (9-n-psicofuranosy-6-aminopurine) is an antibiotic that acts as an inhibitor of xanthosine 5’-phosphate (XMP) aminase with IC50 value of 67 μM. In unfractionated preparations of both strains B-24 and B-35-2, 6.7 X 10-5M psicofuranin inhibited 50% XMP aminase after 2 minutes. Psicofuranine caused a guanine deficiency in enteric bacteria by inhibition of XMP aminase [2]. Psicofuranine-inhibited aminase couldn’t catalyze the aminolysis of the preformed intermediate to AMP and GMP, nor could it condense ATP and XMP to form the intermediate [3]. Psicofuranine had good antibacterial activity in vivo and antitumor activity [1].

References:
[1].  Ladislav J. Hanka. MECHANISM OF ACTION OF PSICOFURANINE. J Bacteriol. 1960 Jul; 80(1): 30–36.
[2].  UDAKA S, MOYED HS. INHIBITION OF PARENTAL AND MUTANT XANTHOSINE 5'-PHOSPHATE AMINASES BY PSICOFURANINE. J Biol Chem. 1963 Aug;238:2797-803.
[3].  Fukuyama TT. Formation of an adenyl xanthosine monophosphate intermediate by xanthosine 5'-phosphate aminase and its inhibition by psicofuranine. J Biol Chem. 1966 Oct 25;241(20):4745-9.