Kinetics of acid-induced degradation of tetra- and dihydrobiopterin in relation to their relevance as biomarkers of endothelial function.
The ratio of the nitric oxide synthase (NOS) cofactor tetrahydrobiopterin (BH(4)) to its oxidized form dihydrobiopterin (BH(2)) has been suggested as an index of endothelial dysfunction. Consequently, much effort has been put into preserving the in vivo equilibrium between these labile analytes. In the present study, we conducted a series of stability experiments in aqueous solutions and blood to identify the most appropriate way of stabilizing BH(4) and BH(2). Based on our results, we are able to recommend that blood samples are immediately stabilized with dithioerythriol and protein precipitation conducted using trichloroacetic acid (TCA).
Faculty of Health and Medical Sciences, Department of Veterinary Disease Biology, University of Copenhagen, Copenhagen, Denmark. alanm@sund.ku.dk
Alan
A
Mortensen
Jens
J
Lykkesfeldt
D015415:Biomarkers / Q000097:blood*; D001708:Biopterins / Q000031:analogs & derivatives* / Q000737:chemistry; D004355:Drug Stability; D004730:Endothelium, Vascular / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010472:Perchlorates / Q000737:chemistry; D010757:Phosphorous Acids / Q000737:chemistry; D014238:Trichloroacetic Acid / Q000737:chemistry
D015415:Biomarkers; D010472:Perchlorates; D010757:Phosphorous Acids; D001708:Biopterins; D014238:Trichloroacetic Acid; C017226:7,8-dihydrobiopterin; C003402:sapropterin; C043639:metaphosphoric acid