Hypoglycin A

Hypoglycin

Names
IUPAC name (S)-2-Amino-3-((S)-2-methylenecyclopropyl)propanoic acid
Other names Hypoglycin A; Hypoglycine; 2-Methylenecyclopropanylalanine
Identifiers
CAS Number	156-56-9 Y
3D model (Jmol)	Interactive image
ChEMBL	ChEMBL1615355 N
ChemSpider	9943349 Y
ECHA InfoCard	100.189.936
PubChem	11768666
InChI InChI=1S/C7H11NO2/c1-4-2-5(4)3-6(8)7(9)10/h5-6H,1-3,8H2,(H,9,10)/t5-,6+/m1/s1 Y Key: OOJZCXFXPZGUBJ-RITPCOANSA-N Y InChI=1/C7H11NO2/c1-4-2-5(4)3-6(8)7(9)10/h5-6H,1-3,8H2,(H,9,10)/t5-,6+/m1/s1 Key: OOJZCXFXPZGUBJ-RITPCOANBH
SMILES O=C(O)[C@@H](N)C[C@@H]1C(=C)C1
Properties
Chemical formula	C7H11NO2
Molar mass	141.17 g·mol−1
Melting point	282 °C (540 °F; 555 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Hypoglycin A is a naturally occurring amino acid derivative found in the unripened fruit of the Ackee tree (Blighia sapida). It is toxic if ingested, and is the causative agent of Jamaican vomiting sickness. A 2017 Lancet report established a link between the consumption of unripened lychees (containing hypoglycin A or methylenecyclopropylglycine (MCPG)) resulting in hypoglycaemia and death from acute toxic encephalopathy.

The entirety of the unripe Ackee fruit is toxic and contains large amounts of hypoglycin. The fruit is safe to eat only when the fruit is allowed to fully open and expose the large black seeds while on the tree. The levels of the toxin decrease over time though from approximately 1000 ppm to around 0.1 ppm in the mature fruit.

Relatives of Ackee, including lychee, longan, and rambutan, can contain enough α-(methylenecyclopropyl)glycine, a homologue of hypoglycin A, in their fruit to cause hypoglycemic encephalopathy in undernourished children, when consumed in large quantities.

Hypoglycin A is a type of Trojan Horse Inhibitor, also known as a Suicide Inhibitor, that in itself does not inhibit any biochemical pathway. However, when mistaken for a branch chain amino acid, the toxicity arises from its metabolites. The branched-chain alpha-keto acid dehydrogenase complex, that would normally convert leucine, isoleucine, or valine into Acyl-CoA derivates, takes this hypoglycin A and metabolizes it into toxic inhibitors; methylene cyclopropyl acetic acid and methylenecyclopropane acetyl esters with carnitine and coenzyme A. The FAD prosthetic group necessary for the beta oxidation of fatty acids associates with the alpha carbon of MCPA-CoA creating an irreversible complex that inhibits the activity of acyl CoA dehydrogenase. In addition, MCPA-CoA blocks some enzymes that are required for gluconeogenesis.