Binding of oxygen to a heme prosthetic group, which would be part of a hemoprotein.
A hemeprotein (or haemprotein; also hemoprotein or haemoprotein), or heme protein, is a protein that contains a heme prosthetic group.[1] They are a very large class of metalloproteins. The heme group confers functionality, which can include oxygen carrying, oxygen reduction, electron transfer, and other processes. Heme is bound to the protein either covalently or noncovalently or both.[2]
The heme consists of iron cation bound at the center of the conjugate base of the porphyrin, as well as other ligands attached to the "axial sites" of the iron. The porphyrin ring is a planar dianionic, tetradentate ligand. The iron is typically Fe2+ or Fe3+. One or two ligands are attached at the axial sites. The porphyrin ring has 4 nitrogen atoms that bind to the iron, leaving two other coordination positions of the iron available for bonding to the histidine of the protein and a divalent atom.[2]
Hemeproteins probably evolved to incorporate the iron atom contained within the protoporphyrin IX ring of heme into proteins. As it makes hemeproteins responsive to molecules that can bind divalent iron, this strategy has been maintained throughout evolution as it plays crucial physiological functions. The serum iron pool maintains iron in soluble form, making it more accessible for cells.[3] Oxygen (O2), nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H2S) bind to the iron atom in heme proteins. Once bound to the prosthetic heme groups, these molecules can modulate the activity/function of those hemeproteins, affording signal transduction. Therefore, when produced in biologic systems (cells), these gaseous molecules are referred to as gasotransmitters.
A model of the Fe-protoporphyrin IX subunit of the Heme B cofactor.
Because of their diverse biological functions and widespread abundance, hemeproteins are among the most studied biomolecules.[4] Data on heme protein structure and function has been aggregated into The Heme Protein Database (HPD), a secondary database to the Protein Data Bank.[5]
^"Heme Prosthetic Group Definition". earth.callutheran.edu. Retrieved 2023-04-27.
^ abNelson DL, Cox MN (2000). Lehninger, Principles of Biochemistry (3rd ed.). New Yorkm: Worth Publishing. ISBN 1-57259-153-6.
^Frazer, David M.; Anderson, Gregory J. (March 2014). "The regulation of iron transport: The Regulation of Iron Transport". BioFactors. 40 (2): 206–214. doi:10.1002/biof.1148. PMID 24132807. S2CID 2998785.
^Reedy CJ, Elvekrog MM, Gibney BR (January 2008). "Development of a heme protein structure-electrochemical function database". Nucleic Acids Research. 36 (Database issue): D307–D313. doi:10.1093/nar/gkm814. PMC 2238922. PMID 17933771.
^Gibney BR. "Heme Protein Database". Brooklyn, NY: Brooklyn College.
A hemeprotein (or haemprotein; also hemoprotein or haemoprotein), or heme protein, is a protein that contains a heme prosthetic group. They are a very...
one of the most widely used and defines a family of proteins known as hemoproteins. Hemes are most commonly recognized as components of hemoglobin, the...
close approach of the Fe-porphyrin assemblies. Cytoglobin Hemoglobin Hemoprotein Neuroglobin Phytoglobin Myoglobinuria - The presence of myoglobin in...
possess cytochrome oxidase or indophenol oxidase (an iron-containing hemoprotein). These both catalyze the transport of electrons from donor compounds...
essential member of the porphyrin group is heme, which is a component of hemoproteins, whose functions include carrying oxygen in the bloodstream. In plants...
reductase, also known as NADPH:ferrihemoprotein oxidoreductase, NADPH:hemoprotein oxidoreductase, NADPH:P450 oxidoreductase, P450 reductase, POR, CPR,...
contains 288 amino acid residues encoded by the HMOX1 gene. HO-1 is not a hemoprotein as it does not contain any heme prosthetic groups. The activity of HO-1...
Cytochromes b5 are ubiquitous electron transport hemoproteins found in animals, plants, fungi and purple phototrophic bacteria. The microsomal and mitochondrial...
The enzyme cytochrome c oxidase or Complex IV, (was EC 1.9.3.1, now reclassified as a translocase EC 7.1.1.9) is a large transmembrane protein complex...
Methemoglobin (British: methaemoglobin, shortened MetHb) (pronounced "met-hemoglobin") is a hemoglobin in the form of metalloprotein, in which the iron...
Catalase is a common enzyme found in nearly all living organisms exposed to oxygen (such as bacteria, plants, and animals) which catalyzes the decomposition...
which is the catabolic action of heme oxygenase on the heme derived from hemoproteins such as hemoglobin. Following the first report that carbon monoxide is...
and the most versatile one. Like all members of this family, it is a hemoprotein, i.e. a protein containing a heme group with an iron atom. In humans...
Myeloperoxidase (MPO) is a peroxidase enzyme that in humans is encoded by the MPO gene on chromosome 17. MPO is most abundantly expressed in neutrophils...
Chemical Classification System Cytochrome b5, ubiquitous electron transport hemoproteins Cytochrome b5, type A, a human microsomal cytochrome b5 HLA-B5, an HLA-B...
homeostasis and reactive oxygen/nitrogen scavenging. It is an intracellular hemoprotein expressed in the central and peripheral nervous system, cerebrospinal...
Leghemoglobin (also leghaemoglobin or legoglobin) is an oxygen-carrying phytoglobin found in the nitrogen-fixing root nodules of leguminous plants. It...
expelling carbon dioxide as carbaminohemoglobin. Additionally, many other hemoproteins such as myoglobin, Cytochrome P450, and mitochondrial cytochrome oxidase...
hemoglobin variants). Structural variations and mutations across other hemoproteins likewise affect carbon monoxide's interaction with the heme prosthetic...
Global Information
