Sepiapterin reductase
Encyclopedia
In enzymology, a sepiapterin reductase (SPR) is an enzyme
that catalyzes
the following chemical reaction
:
Thus, the two substrates
of this enzyme are 7,8-dihydrobiopterin (DHB, BH2) and NADP+, whereas its three products
are tetrahydrobiopterin
(THB, BH4) or sepiapterin
, NADPH
, and a single hydrogen ion
(H+).
This enzyme belongs to the family
of oxidoreductase
s, to be specific, those acting on the CH-OH group
of donor
with NAD+ or NADP+ as acceptor
. The systematic name
of this enzyme class is 7,8-dihydrobiopterin:NADP+ oxidoreductase. This enzyme participates in folate biosynthesis.
have been solved for this class of enzymes, with Protein Data Bank
(PDB) accession code
s , , , , and .
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 following 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...
:
- 7,8-dihydrobiopterin + NADPH + H+
tetrahydrobiopterin + NADP+
Thus, the two 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 7,8-dihydrobiopterin (DHB, BH2) and NADP+, whereas its three 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 tetrahydrobiopterin
Tetrahydrobiopterin
Tetrahydrobiopterin or sapropterin is a naturally occurring essential cofactor of the three aromatic amino acid hydroxylase enzymes, used in the degradation of amino acid phenylalanine and in the biosynthesis of the neurotransmitters serotonin , melatonin, dopamine, norepinephrine ,...
(THB, BH4) or sepiapterin
Sepiapterin
Sepiapterin is a product of sepiapterin reductase....
, NADPH
Nicotinamide adenine dinucleotide phosphate
Nicotinamide adenine dinucleotide phosphate, abbreviated NADP or TPN in older notation , is a coenzyme used in anabolic reactions, such as lipid and nucleic acid synthesis, which require NADPH as a reducing agent....
, and a single hydrogen ion
Hydrogen ion
Hydrogen ion is recommended by IUPAC as a general term for all ions of hydrogen and its isotopes.Depending on the charge of the ion, two different classes can be distinguished: positively charged ions and negatively charged ions....
(H+).
This enzyme belongs to the family
Protein family
A protein family is a group of evolutionarily-related proteins, and is often nearly synonymous with gene family. The term protein family should not be confused with family as it is used in taxonomy....
of oxidoreductase
Oxidoreductase
In biochemistry, an oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule to another...
s, to be specific, those acting on the CH-OH group
Functional group
In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of...
of donor
Electron donor
An electron donor is a chemical entity that donates electrons to another compound. It is a reducing agent that, by virtue of its donating electrons, is itself oxidized in the process....
with NAD+ or NADP+ as 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....
. The systematic name
Systematic name
A systematic name is a name given in a systematic way to one unique group, organism, object or chemical substance, out of a specific population or collection...
of this enzyme class is 7,8-dihydrobiopterin:NADP+ oxidoreductase. This enzyme participates in folate biosynthesis.
Structural Studies
As of late 2007, five structuresTertiary structure
In biochemistry and molecular biology, the tertiary structure of a protein or any other macromolecule is its three-dimensional structure, as defined by the atomic coordinates.-Relationship to primary structure:...
have been solved for this class of enzymes, with Protein Data Bank
Protein Data Bank
The Protein Data Bank is a repository for the 3-D structural data of large biological molecules, such as proteins and nucleic acids....
(PDB) accession code
Access Code
Access code may refer to:In authentication:* Password, a secret word.* Personal identification number , a secret numeric code.In telecommunications:* National access code, used to dial a domestic call....
s , , , , and .