Assay for erythrocyte uroporphyrinogen I synthase activity, with porphobilinogen as substrate

We describe a convenient, economical procedure for measuring uroporphyrinogen I synthase (EC 4.3 1.8) activity in erythrocytes, the results of which can be used to diagnose acute intermittent porphyria, in either its latent or acute stage. By limiting the test reaction sequence to the conversion of...

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Bibliographic Details
Published inClinical chemistry (Baltimore, Md.) Vol. 26; no. 8; pp. 1182 - 1185
Main Authors Ford, RE, Ou, CN, Ellefson, RD
Format Journal Article
LanguageEnglish
Published England Am Assoc Clin Chem 01.07.1980
Subjects
Ammonia-Lyases - blood
Erythrocytes - enzymology
Humans
Hydroxymethylbilane Synthase - blood
Kinetics
Lead - pharmacology
Porphobilinogen
Porphobilinogen Synthase - antagonists & inhibitors
Porphobilinogen Synthase - blood
Substrate Specificity
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Summary:We describe a convenient, economical procedure for measuring uroporphyrinogen I synthase (EC 4.3 1.8) activity in erythrocytes, the results of which can be used to diagnose acute intermittent porphyria, in either its latent or acute stage. By limiting the test reaction sequence to the conversion of porphobilinogen to porphyrins, we eliminated several disadvantages of alternative methods in which delta-aminolevulinate is used as substrate. The latter assay was inhibited by lead; our procedure was not. Our procedure also gave greater porphyrin synthesis with less substrate. Erythrocytes of healthy women presented a mean activity of 12.4 nmol of porphyrin formed per liter per second; erythrocytes of healthy men presented a mean activity of 11.0 nmol/L per second. The within-run coefficient of variation (CV) for our assay was 1.8%; the between-run CV was 3.1%.
Bibliography:ObjectType-Article-1
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ISSN:0009-9147
1530-8561
DOI:10.1093/clinchem/26.8.1182