Heme degradation and its physiological importance

Notes

BCH 202 HEME DEGRADATION HEME • A heme is a metal-containing prosthetic group of several proteins, which consists of ferrous iron embedded in a porphyrin ring system coordinated by four nitrogen atoms. • It is a ring-shaped iron-containing molecular component of hemoglobin, needed to bind oxygen in the bloodstream. • It plays an indispensable role in various biological processes such as respiration, oxygen metabolism, oxygen transfer, photosynthetic electron transportation, and oxidative stress responses. • It is the primary source of functional, bioavailable iron and accounts for 95% of iron in the human body. • Heme is an essential component of hemoglobin and responsible for the characteristic red pigmentation of blood. Heme contd • It is also an important component of myoglobin and other heme- containing proteins (including enzymes). • These proteins are vital for oxygen transport in the blood, • oxygen storage in tissues (particularly skeletal muscle and heart), • Proteins in the mitochondrial electron transport system (e.g., cytochromes), and • Heme enzymes (including catalase, guanyl cyclase, nitric oxide synthase etc). • Each of these macromolecules mediates physiological pr...