Determination of erythrocyte hydroxymethylbilane synthase activity and its application for study of acute intermittent porphyria
Lee, F.Y.; Hsiao, K.J.; Tsai, Y.T.; Lee, S.D.; Wu, S.J.; Jeng, H.S.
Journal of the Formosan Medical Association 87(11): 1029-1035
1988
ISSN/ISBN: 0371-7682 PMID: 3235962 Document Number: 310944
We describe a convenient procedure for measuring hydroxymethylbilane synthase activity in erythrocyte, which can be used to diagnose acute intermittent porphyria in either latent or acute stage. In assaying erythrocyte hydroxymethylbilane synthase with porphobilinogen as a substrate, we found that the hydroxymethylbilane synthase had an optimum pH at 8.2. The Km value of the enzyme estimated in 6 healthy persons was 14.0 .+-. 0.8 .mu.mol/l (mean .+-. SE). The within-run and between-run coefficients of variation for our method were 3.8% and 4.4%, respectively. In 133 apparently healthy adults, the reference range of hydroxymethylbilane synthase with porphobilinogen as a substrate was estimated to range from 30.0 to 73.7 nmol of porphyrin formed per hour per milliliter of red blood cells. The age or sex difference was insignificant. Application of this method for diagnosis fo acute intermittent porphyria and for identifying carriers of the disease was demonstrated in an affected Chinese family.