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Record Information
StatusExpected but not Quantified
Creation Date2012-09-11 17:41:17 UTC
Update Date2019-01-11 19:41:55 UTC
Secondary Accession Numbers
  • HMDB31148
Metabolite Identification
Common NameProtochlorophyllide
DescriptionProtochlorophyllide is found in fruits. Protochlorophyllide is isolated from the seed husks of Cucurbita pepo Chlorophyll itself is bound to proteins and can transfer the absorbed energy in the required direction. Protochlorophyllide, differently, mostly occurs in the free form and under light conditions acts as photosensitizer, forming highly toxic free radicals. Hence plants need an efficient mechanism of regulating the amount of chlorophyll precursor. In angiosperms, this is done at the step of D-Aminolevulinic acid (ALA), one of the intermediate compounds in the biosynthesis pathway. Plants that are fed by ALA accumulate high and toxic levels of protochlorophyllide, so do the mutants with the damaged regulatory system. Despite of numerous past attempts to find the mutant that overacumulates protochlorophyllide under usual conditions, only one such gene (flu) is currently (2009) known. Flu (first described in ) is a nuclear - encoded, chloroplast - located protein that appears containing only protein - protein interaction sites. It is currently not know which other proteins interact through this linker. The regulatory protein is a transmembrane protein that is located in the thylakoid membrane. Later it was discovered that Tigrina mutants in barley, known long time ago, are also mutated in the same gene It is not obvious why no mutants of any other gene were observed; maybe mutations in other proteins, involved into the regulatory chain, are fatal. Flu is a single gene, not a member of the gene family. Protochlorophyllide , more accurate monovinyl protochlorophyllide, is an immediate precursor of chlorophyll a that lacks the phytol side chain of chlorophyll. Unlike chlorophyll, protochlorophyllide is highly fluorescent; mutants that accumulate it glow in red if irradiated by the blue lightIn Angiosperms, the last step, conversion of protochlorophyllide to chlorophyll, is light - dependent and such plants are pale (etiolated) if grown in the darkness. Gymnosperms, algae, and photosynthetic bacteria additionally have another, light - independent enzyme and grow green in the darkness as well. The enzyme that converts protochlorophyllide to chlorophyll is protochlorophyllide reductase , EC There are two structurally unrelated proteins with this activity: the light - dependent and the dark - operative. The light dependent reductase needs light to operate. The dark - operative version is a completely different protein, consisting of three subunits that exhibit significant sequence similarity to the three subunits of nitrogenase, which catalyzes the formation of ammonia from dinitrogen. This enzyme might be evolutionary older but (being similar to nitrogenase) is highly sensitive to free oxygen and does not work if its concentration exceeds about 3 %. Hence the alternative, light dependent version needed to evolve
Protochlorophyllide aChEBI
Chemical FormulaC35H32MgN4O5
Average Molecular Weight612.969
Monoisotopic Molecular Weight612.22231185
IUPAC Name(5R)-23-(2-carboxyethyl)-17-ethenyl-12-ethyl-5-(methoxycarbonyl)-8,13,18,22-tetramethyl-6-oxo-2,25lambda5,26lambda5,27-tetraaza-1-magnesanonacyclo[^{1,16}.0^{2,9}.0^{3,7}.0^{4,24}.0^{11,26}.0^{21,25}.0^{19,27}]heptacosa-3(7),4(24),8,10,12,14(26),15,17,19,21(25),22-undecaene-25,26-bis(ylium)-1,1-diuide
Traditional Name(5R)-23-(2-carboxyethyl)-17-ethenyl-12-ethyl-5-(methoxycarbonyl)-8,13,18,22-tetramethyl-6-oxo-2,25lambda5,26lambda5,27-tetraaza-1-magnesanonacyclo[^{1,16}.0^{2,9}.0^{3,7}.0^{4,24}.0^{11,26}.0^{21,25}.0^{19,27}]heptacosa-3(7),4(24),8,10,12,14(26),15,17,19,21(25),22-undecaene-25,26-bis(ylium)-1,1-diuide
CAS Registry Number14751-08-7
InChI Identifier
Chemical Taxonomy
DescriptionThis compound belongs to the class of organic compounds known as metalloporphyrins. These are polycyclic compounds containing a porphyrin moiety and a metal atom.
KingdomOrganic compounds
Super ClassOrganoheterocyclic compounds
ClassTetrapyrroles and derivatives
Sub ClassMetallotetrapyrroles
Direct ParentMetalloporphyrins
Alternative Parents
  • Metalloporphyrin
  • Porphyrin
  • Aryl ketone
  • Aryl alkyl ketone
  • Dicarboxylic acid or derivatives
  • Substituted pyrrole
  • 1,3-dicarbonyl compound
  • Heteroaromatic compound
  • Methyl ester
  • Pyrrole
  • Carboxylic acid ester
  • Carboxylic acid salt
  • Ketone
  • Carboxylic acid
  • Azacycle
  • Carboxylic acid derivative
  • Organooxygen compound
  • Organonitrogen compound
  • Organic oxide
  • Organic cation
  • Organic salt
  • Hydrocarbon derivative
  • Carbonyl group
  • Aromatic heteropolycyclic compound
Molecular FrameworkAromatic heteropolycyclic compounds
External DescriptorsNot Available

Route of exposure:


Biological location:

Physical Properties
StateNot Available
Experimental Properties
Melting PointNot AvailableNot Available
Boiling PointNot AvailableNot Available
Water SolubilityNot AvailableNot Available
LogPNot AvailableNot Available
Predicted Properties
Water Solubility0.042 g/LALOGPS
pKa (Strongest Acidic)3.68ChemAxon
pKa (Strongest Basic)-7.1ChemAxon
Physiological Charge-2ChemAxon
Hydrogen Acceptor Count4ChemAxon
Hydrogen Donor Count1ChemAxon
Polar Surface Area98.29 ŲChemAxon
Rotatable Bond Count7ChemAxon
Refractivity173.94 m³·mol⁻¹ChemAxon
Polarizability69.78 ųChemAxon
Number of Rings9ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Not Available
Biological Properties
Cellular Locations
  • Cytoplasm
  • Extracellular
Biospecimen LocationsNot Available
Tissue LocationsNot Available
Normal Concentrations
Not Available
Abnormal Concentrations
Not Available
Associated Disorders and Diseases
Disease ReferencesNone
Associated OMIM IDsNone
DrugBank IDNot Available
Phenol Explorer Compound IDNot Available
FoodDB IDNot Available
KNApSAcK IDNot Available
Chemspider ID388880
KEGG Compound IDC02880
BioCyc IDNot Available
BiGG IDNot Available
Wikipedia LinkProtochlorophyllide
METLIN IDNot Available
PubChem CompoundNot Available
PDB IDNot Available
ChEBI ID16673
Synthesis ReferenceNot Available
Material Safety Data Sheet (MSDS)Not Available
General References
  1. Meskauskiene R, Nater M, Goslings D, Kessler F, op den Camp R, Apel K: FLU: a negative regulator of chlorophyll biosynthesis in Arabidopsis thaliana. Proc Natl Acad Sci U S A. 2001 Oct 23;98(22):12826-31. Epub 2001 Oct 16. [PubMed:11606728 ]
  2. (). Yannai, Shmuel. (2004) Dictionary of food compounds with CD-ROM: Additives, flavors, and ingredients. Boca Raton: Chapman & Hall/CRC.. .