Related Experiment Video
Updated: May 3, 2026

Measurement of Heme Synthesis Levels in Mammalian Cells
Published on: July 9, 2015
Porphyrin metabolism and haem biosynthesis in Gilbert's syndrome
Abstract:
Studies in 14 patients with unconjugated hyperbilirubinaemia caused by Gilbert's syndrome have revealed abnormalities of the enzymes of haem biosynthesis measured in peripheral blood cells. The activity of the penultimate enzyme of haem biosynthesis protoporphyrinogen (PROTO) oxidase was reduced at 3.1 +/- 2.6 nmol PROTO/g protein/h (mean +/- ISD) compared with 8.2 +/- 5.1 in controls (p less than 0.005). This was associated with a compensatory increase in the activity of the initial and rate controlling enzyme of the pathway delta-aminolaevulinic acid (ALA) synthase at 866 +/- 636 nmol ALA/g/protein/h compared with 156 +/- 63 in controls (p less than 0.001). Unlike variegate porphyria in which there is a genetic deficiency of PROTO oxidase there was no increased excretion of porphyrins or their precursors in Gilbert's syndrome. Accentuation and subsequent correction of the unconjugated hyperbilirubinaemia with rifampicin produced reciprocal changes in PROTO oxidase activity indicating that bilirubin may be inhibiting the activity of this enzyme.
More Related Videos
10:05Stimulation of Stem Cell Niches and Tissue Regeneration in Mouse Skin by Switchable Protoporphyrin IX-Dependent Photogeneration of Reactive Oxygen Species In Situ
Published on: May 8, 2020
10:06Author Spotlight: Porphyrin-Modified Beads for Use as Compensation Controls in Flow Cytometry
Published on: March 24, 2023
Related Concept Videos
Inborn Errors of Metabolism
Pharmacogenetics of Phase I Enzymes: Cytochrome P450 Isozymes
Pharmacogenetics of Phase II Enzymes: N-acetyltransferase, Thiopurine S-methyltransferase, UDP-glucuronosyltransferase
Drug toxicity: Idiosyncratic Reactions
Biosynthesis of Nucleic Acids
Jaundice