L-Biopterin is the oxidized form of tetrahydro-L-biopterin (BH4), a nitric oxide synthase (NOS) cofactor. L-Biopterin can be reduced to BH4 via thioredoxin reductase followed by dihydropteridine reductase or reduced glutathione. It is extremely toxic to human melanocytes in culture (IC50 = 0.2 µM after 48 hrs)....

p38 is a member of the mitogen-activated protein kinase (MAPK) superfamily of enzymes that play an important role in signal transduction. PD 169316 is a selective inhibitor of p38 MAPK. It inhibits p38 MAPK with an IC50 of 89 nM, whereas the IC50s are >100-fold higher for extracellular signal-regulated kinase (ERK)...

19-HETE is one of the major cytochrome P450 (CYP450) metabolites of arachidonic acid that is released from the kidney in response to angiotensin II. When formed by the CYP2E1 isoform, 19-HETE is composed of 70% and 30% of the (S) and (R) stereoisomers, respectively. Both 19(S)- and 19(R)-HETE are potent vasodilators...

Cylindrospermopsin, a tricyclic uracil derivative, is a cyanobacterial toxin that was first discovered in an algal bloom contaminating a local drinking supply on Palm Island in Queensland, Australia after an outbreak of a mysterious disease. Cylindrospermopsin targets protein and glutathione synthesis in hepatocytes...