iScience 2021 Mar 6;24(3):102152. Epub 2021 Feb 6.
Department of Chemistry, University of Eastern Finland, 80130 Joensuu, Finland.
Porphobilinogen deaminase (PBGD), the third enzyme in the heme biosynthesis, catalyzes the sequential coupling of four porphobilinogen (PBG) molecules into a heme precursor. Mutations in PBGD are associated with acute intermittent porphyria (AIP), a rare metabolic disorder. We used Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to demonstrate that wild-type PBGD and AIP-associated mutant R167W both existed as holoenzymes (E) covalently attached to the dipyrromethane cofactor, and three intermediate complexes, ES, ES, and ES, where S represents PBG. Read More