Steroid 17alpha-monooxygenase
Encyclopedia
In enzymology, a steroid 17alpha-monooxygenase is an enzyme
that catalyzes
the chemical reaction
The 3 substrates
of this enzyme are steroid
, an electron acceptor
AH2, and O2
, whereas its 3 products
are 17alpha-hydroxysteroid, the reduction product A, and H2O
.
This enzyme belongs to the family of oxidoreductase
s, specifically those acting on paired donors, with O2 as oxidant and incorporation or reduction of oxygen. The oxygen incorporated need not be derive from O miscellaneous. The systematic name of this enzyme class is steroid,hydrogen-donor:oxygen oxidoreductase (17alpha-hydroxylating). Other names in common use include steroid 17alpha-hydroxylase, cytochrome P-45017alpha, cytochrome P-450 (P-45017alpha,lyase), and 17alpha-hydroxylase-C17,20 lyase. This enzyme participates in c21-steroid hormone metabolism. It has 3 cofactors
: NADH, NADPH, and Heme
.
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
that catalyzes
Catalysis
Catalysis is the change in rate of a chemical reaction due to the participation of a substance called a catalyst. Unlike other reagents that participate in the chemical reaction, a catalyst is not consumed by the reaction itself. A catalyst may participate in multiple chemical transformations....
the chemical reaction
Chemical reaction
A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity...
- a steroid + AH2 + O2
a 17alpha-hydroxysteroid + A + H2O
The 3 substrates
Substrate (biochemistry)
In biochemistry, a substrate is a molecule upon which an enzyme acts. Enzymes catalyze chemical reactions involving the substrate. In the case of a single substrate, the substrate binds with the enzyme active site, and an enzyme-substrate complex is formed. The substrate is transformed into one or...
of this enzyme are steroid
Steroid
A steroid is a type of organic compound that contains a characteristic arrangement of four cycloalkane rings that are joined to each other. Examples of steroids include the dietary fat cholesterol, the sex hormones estradiol and testosterone, and the anti-inflammatory drug dexamethasone.The core...
, an electron acceptor
Electron acceptor
An electron acceptor is a chemical entity that accepts electrons transferred to it from another compound. It is an oxidizing agent that, by virtue of its accepting electrons, is itself reduced in the process....
AH2, and O2
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
, whereas its 3 products
Product (chemistry)
Product are formed during chemical reactions as reagents are consumed. Products have lower energy than the reagents and are produced during the reaction according to the second law of thermodynamics. The released energy comes from changes in chemical bonds between atoms in reagent molecules and...
are 17alpha-hydroxysteroid, the reduction product A, and H2O
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
.
This enzyme belongs to the family of oxidoreductase
Oxidoreductase
In biochemistry, an oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule to another...
s, specifically those acting on paired donors, with O2 as oxidant and incorporation or reduction of oxygen. The oxygen incorporated need not be derive from O miscellaneous. The systematic name of this enzyme class is steroid,hydrogen-donor:oxygen oxidoreductase (17alpha-hydroxylating). Other names in common use include steroid 17alpha-hydroxylase, cytochrome P-45017alpha, cytochrome P-450 (P-45017alpha,lyase), and 17alpha-hydroxylase-C17,20 lyase. This enzyme participates in c21-steroid hormone metabolism. It has 3 cofactors
Cofactor (biochemistry)
A cofactor is a non-protein chemical compound that is bound to a protein and is required for the protein's biological activity. These proteins are commonly enzymes, and cofactors can be considered "helper molecules" that assist in biochemical transformations....
: NADH, NADPH, and Heme
Heme
A heme or haem is a prosthetic group that consists of an iron atom contained in the center of a large heterocyclic organic ring called a porphyrin. Not all porphyrins contain iron, but a substantial fraction of porphyrin-containing metalloproteins have heme as their prosthetic group; these are...
.