In enzymology, a phytochromobilin:ferredoxin oxidoreductase is an enzyme

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...

-phytochromobilin + oxidized ferredoxin biliverdin IXalpha + reduced ferredoxin

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 (3Z)-phytochromobilin and oxidized ferredoxin

Ferredoxin

Ferredoxins are iron-sulfur proteins that mediate electron transfer in a range of metabolic reactions. The term "ferredoxin" was coined by D.C. Wharton of the DuPont Co...

, whereas its two 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 biliverdin IXalpha and reduced ferredoxin

Ferredoxin

Ferredoxins are iron-sulfur proteins that mediate electron transfer in a range of metabolic reactions. The term "ferredoxin" was coined by D.C. Wharton of the DuPont Co...

.

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 the CH-CH group of donor with an iron-sulfur protein as acceptor. The systematic name of this enzyme class is (3Z)-phytochromobilin:ferredoxin oxidoreductase. Other names in common use include HY2, PPhiB synthase, and phytochromobilin synthase. This enzyme participates in porphyrin

Porphyrin

Porphyrins are a group of organic compounds, many naturally occurring. One of the best-known porphyrins is heme, the pigment in red blood cells; heme is a cofactor of the protein hemoglobin. Porphyrins are heterocyclic macrocycles composed of four modified pyrrole subunits interconnected at...

 and chlorophyll

Chlorophyll

Chlorophyll is a green pigment found in almost all plants, algae, and cyanobacteria. Its name is derived from the Greek words χλωρος, chloros and φύλλον, phyllon . Chlorophyll is an extremely important biomolecule, critical in photosynthesis, which allows plants to obtain energy from light...

metabolism.