Palladium (CED0001146)

Palladium (Pd) is an exogenous solid with an average molecular weight of 106.42 g/mol. Palladium belongs to the homogeneous transition metal compounds, a class of homogeneous metal compounds within the inorganic compounds. It serves as an industrial catalyst (PMC12492045, PMC13054246). This element is released from 52 recorded sources, including electrical and electronic equipment such as antennas, amplifiers, coils, and adjustable resistors; household items including medals, coins, watch chains, and key rings; building and construction materials like floors, fencing, and ceilings; food, food processing and cookware including the processing of meats and fish and fermentation processes for beer; and household cleaning and consumer products such as bleaching agents and smoking requisites. It has not been detected in polyethylene terephthalate or polystyrene. Inhalation is a documented exposure route (PMC11393805). Palladium has a therapeutic effect on cancer (PMC10671087) and is used as a treatment for multiple myeloma (PMC11215383, PMC6223128, PMC9387011), though it is associated with thrombocytopenia, pneumonia, and neutropenia (PMC11215383). At the molecular level, palladium targets four proteins. It inhibits creatine kinase M-type (CKM) by forming a complex with essential SH groups. Additionally, palladium irreversibly inhibits prolyl 4-hydroxylase subunit alpha-1 (P4HA1), prolyl 4-hydroxylase subunit alpha-2 (P4HA2), and transmembrane prolyl 4-hydroxylase (P4HTM) by replacing Fe2+ in the active site to form a strong complex with the enzyme.