Mainly, lead present in blood located in eryhrocytes. Its toxicity comes from the ability to create complexes with the 
negatively charged ligands. The following journal will provide you with a review outlines lead distribution (contamination) and its influence on purine conversion pathways in human erythrocites.
Sections describe on this Biochemistry Journal are Role of the Nucleotide Purines in Erythrocyte Metabolism Regulation, Purine Nucleotides Metabolism, Lead Ion Influenced Disorders in the Erythrocyte Energy Metabolism, and Mechanisms of the Toxic Effect of Lead. Also there are several pathway illustration scheme such biological significance of some adenilate containing molecules, The synthesis PRPP in erythrocytes, and Pathway of purine metabolism in erythrocytes (click scheme to enlarge) .
See more on How Lead Contamination Influence Purin Metabolism Pathways in this biochemistry journal (source: pjos.com)
