Search results
Results From The WOW.Com Content Network
Heme (American English), or haem (Commonwealth English, both pronounced /hi:m/ HEEM), is a ring-shaped iron-containing molecular component of hemoglobin, which is necessary to bind oxygen in the bloodstream. It is composed of four pyrrole rings with 2 vinyl and 2 propionic acid side chains. [1] Heme is biosynthesized in both the bone marrow and ...
With a total of 26 π-electrons, of which 18 π-electrons form a planar, continuous cycle, the porphyrin ring structure is often described as aromatic. [ 2 ] [ 3 ] One result of the large conjugated system is that porphyrins typically absorb strongly in the visible region of the electromagnetic spectrum, i.e. they are deeply colored.
Pyrrole is a heterocyclic, aromatic, organic compound, a five-membered ring with the formula C 4 H 4 NH. [3] It is a colorless volatile liquid that darkens readily upon exposure to air. Substituted derivatives are also called pyrroles, e.g., N -methylpyrrole, C 4 H 4 NCH 3 .
Porphyrins, including heme, the core of hemoglobin; Chlorins, including those at the core of chlorophyll. Cyclic tetrapyrroles having three one-carbon bridges and one direct bond between the pyrroles include: Corrins, including the cores of cobalamins, when complexed with a cobalt ion.
The general term protoporphyrin refers to porphine derivatives that have the outer hydrogen atoms in the four pyrrole rings replaced by other functional groups. The prefix proto often means 'first' in science nomenclature (such as carbon protoxide), hence Hans Fischer is thought to have coined the name protoporphyrin as the first class of porphyrins. [3]
In biochemistry, a porphyrinogen is a member of a class of naturally occurring compounds with a tetrapyrrole core, a macrocycle of four pyrrole rings connected by four methylene bridges. [1] They can be viewed as derived from the parent compound hexahydroporphine by the substitution of various functional groups for hydrogen atoms in the ...
Four pyrrole rings are joined in a ring structure called a porphyrin. The rings of porphyrin are components of hemoglobin, myoglobin, vitamin B12, chlorophyll, and cytochromes. In the centers of heme in hemoglobin, myoglobin, and cytochromes, iron is an ion; in the first two, iron ion is bound to oxygen.
The structure of the molecule can be described as molecule of pyrrole with sidechains substituted for hydrogen atoms at positions 2, 3 and 4 in the ring (1 being the nitrogen atom); respectively, an aminomethyl group −CH 2 −NH 2, an acetic acid (carboxymethyl) group −CH 2 −COOH, and a propionic acid (carboxyethyl) group −CH 2 −CH 2 ...