Porphobilinogen deaminase is an enzyme that plays a crucial role in the biosynthesis of heme, a vital component of hemoglobin in red blood cells. It catalyzes the conversion of porphobilinogen into hydroxymethylbilane, which is an important step in the production of heme. This enzyme is primarily found in the liver and bone marrow. Deficiency in porphobilinogen deaminase can lead to a condition known as acute intermittent porphyria, which is characterized by abdominal pain, neurological symptoms, and changes in urine color. Understanding this enzyme is essential for diagnosing and managing porphyrias, a group of disorders related to heme production.