Lead ions in the human metabolism replace native metallic ions in several key proteins, for example: zinc cations in the ALAD protein, which is also known as Porphobilinogen synthase.
ATP synthase | NO synthase | ATP synthase subunit C | Salutaridine synthase | Ribbon diagram of Sucrose Synthase-1 3S27 Structure, isolated from ''Arabidopsis thaliana | Porphobilinogen synthase | Porphobilinogen deaminase | Phosphoribosylaminoimidazolesuccinocarboxamide synthase |