What Is Protoporphyrin?
Protoporphyrin is the generic name for porphyrins, which are organic compounds consisting of a porphine ring with four methyl groups, two vinyl groups, and two propionic acid groups attached to it.
The chemical formula is C34H34N4O4. Unless otherwise specified, it refers to protoporphyrin IX, and its CAS registration number is 553-12-8.
It belongs to the porphyrin family of tetrapyrroles. Protoporphyrins combine with iron, manganese, zinc, and magnesium to form metalloporphyrins. The divalent iron complex of protoporphyrins is the pigment of hemoglobin.
Uses of Protoporphyrin
Protoporphyrin is a substance used in pharmaceuticals as protoporphyrin disodium. Its indications include improvement of liver function in chronic liver disease, and it is used to treat cirrhosis, chronic hepatitis, and liver dysfunction. Protoporphyrins are also precursors to heme and chlorophyll in the body.
In testing and research applications, protoporphyrins are used as standards for protoporphyrin assays, for fluorescence spectral analysis, and for processing cells in cell culture to study heme-mediated ferroportin 1 transcription. Protoporphyrin IX is also known to activate soluble guanylate cyclase.
Properties of Protoporphyrin
Protoporphyrin IX is represented by the molecular formula C34H34N4O4 and has a molecular weight of 562.66. It has a density of 1.27 g/mL and is a dark purple powder at room temperature.
As a pharmaceutical product, it is used as disodium protoporphyrin. The sodium salt is a reddish-purple to blackish-purple powder at room temperature with a melting point above 300°C. It is odorless and has a weak salty taste. It is soluble in water and ethanol, and almost insoluble in diethyl ether and chloroform.
Types of Protoporphyrin
Protoporphyrin IX is sold primarily as a reagent product for research and development. It is available in volumes of 5 mg, 25 mg, 1 g, etc., which are relatively small volumes among laboratory volumes.
In addition to regular protoporphyrin, 2H6-protoporphyrin IX is also sold as a stable isotope standard. Many derivatives are also offered, including zinc protoporphyrin, protoporphyrin IX dimethyl ester, hemin, etc.
Other Information on Protoporphyrin
Biosynthesis of Protoporphyrins
Protoporphyrin is synthesized in vivo through several enzymatic reactions using δ-aminolevulinic acid as the starting material. The specific enzymatic reactions are as follows:
1. Formation of Porphobilinogen With a Pyrrole Ring Structure
2. dehydration-condensation of two molecules of δ-aminolevulinic acid by aminolevulinic acid dehydratase
2. Formation of Hydroxymethylbilane
4 molecules of porphobilinogen are combined by porphobilinogen deaminase to form 4 linearly linked pyrroles by deamination of ammonia.
3. Synthesis of Uroporphyrinogen III
Hydroxymethylbilane is condensed by uroporphyrinogen III synthase to form a ring structure.
4. Synthesis of Coproporphyrinogen III
Four acetate groups are decarboxylated by uroporphyrinogen decarboxylase to form methyl groups.
5. Synthesis of Protoporphyrinogen IX
Two propionate groups are oxidized by coproporphyrinogen oxidase to vinyl groups.
6. Synthesis of Protoporphyrin IX
Oxidized by protoporphyrinogen oxidase.