BIOCHEMISTRY A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z                    HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site porphyrins A naturally occurring isomer of protoporphyrin demonstrating the typical porphyrin ring structure Water-soluble, nitrogen-containing organic compounds of great biological importance which are found in a variety of pigments, including hemoglobin, chlorophyll a and b, the cytochromes (concerned with respiration in cells), and the enzymes catalase and peroxidase. Porphyrins are variations on the basic structure of porphin. A variety of side groups can be attached at 8 different locations around the molecule and a complex can be formed with a centrally located, heavy metal atom. In hemoglobin this metal is iron, while in chlorophyll it is magnesium. Related category    • BIOCHEMISTRY Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP