In all of eight tested human cells and cell lines with inducible indoleamine 2,3-dioxygenase (EC 1.13.11.17) tetrahydrobiopterin biosynthesis was activated by interferon-gamma. This was demonstrated by GTP cyclohydrolase I (EC 3.5.4.16) activities and intracellular neopterin and biopterin concentrations. Pteridine synthesis was influenced by extracellular tryptophan. In T 24-cell extracts, subm...

Carbon paste electrode was modified by disodium 2,4-diamino-7-methylbenzo[g] pteridine-5,10-dioxide to fabricate a sensor for potentiometric determination of vanadyl ion (VO2+) in aqueous medium. The new ligand was synthesized in three steps with high yield. The optimal composition of the carbon paste was made of graphite powder (64.5%), ionophore (16.6%), paraffin oil (17.8%), a...

Dihydrofolate reductase (EC 1.5.1.3) catalyses the NADPHdependent reduction of dihydrofolate to tetrahydrofolate. The product, together with other reduced folates, serves as a cofactor in a variety of 1-carbon transfers in the biosynthesis of purines, pyrimidines and amino acids (Blakley, 1969). The enzyme is considered to be the major cellular receptor for several important drugs including met...

background recurrent pregnancy loss (rpl) is a serious problem for pregnancy. there is evidence that vascular complications play a principal role in rpl. methylenetetrahydrofolate reductase (mthfr) is a key enzyme in folate metabolism. polymorphisms (c677t, a1298c) of mthfr gene are associated with decreased mthfr activity. objectives the aim of this study was to determine the association betwe...

Tetrahydrobiopterin (BH(4)) is a cofactor for aromatic amino acid hydroxylases and nitric oxide synthase. The biosynthesis includes two reduction steps catalyzed by sepiapterin reductase. An intermediate, 6-pyruvoyltetrahydropterin (PPH(4)) is reduced to 1(')-oxo-2(')-hydroxypropyl-tetrahydropterin (1(')-OXPH(4)) or 1(')-hydroxy-2(')-oxopropyl-tetrahydropterin (2(')-OXPH(4)), which is further c...

Mallette and coworkers (1) were the first to synthesize 2,4-diaminopteridine and four derivatives of this type, namely the 6,7-dimethyl, diphenyl, phenanthro, and acenaphtho compounds. Daniel et al. (2) and Daniel and Norris (3) reported strong inhibitory properties of these compounds for the growth of Streptococcus jaecalis and Lactobacdlus case-i which require preformed pteroylglutamic acid (...