uroporphyrin

noun

uro·​por·​phy·​rin ˌyu̇r-ō-ˈpȯr-fə-rən 

: any of four isomeric porphyrins C₄₀H₃₈N₄O₁₆ which contain acetic acid and propionic acid groups on the porphin nucleus and are closely related to the coproporphyrins