our study aimed at investigating the biosynthesis of unconjugated pterins in highly purified human macrophages and t lymphocytes before and during stimulation with supernatants of activated t cells or with recombinant human interferon-gamma ( ifn-gamma ) by monitoring the following parameters : substrate concentration ( gtp , guanosine triphosphate ) , activity of the enzyme initiating the biosynthesis of pterins ( gtp-cyclohydrolase i ) and product concentrations of total neopterin , biopterin , and pterin .
C0068527
neopterin
C0005562
biopterin