Aminolevulinic acid

δ-Aminolevulinic acid

Systematic (IUPAC) name
5-amino-4-oxo-pentanoic acid
Clinical data
Pregnancy category	C
Legal status	℞ (Prescription only)
Identifiers
CAS Number	106-60-5 Y
ATC code	L01XD04 (WHO)
PubChem	CID: 137
IUPHAR/BPS	4784
DrugBank	DB00855 Y
ChemSpider	134 Y
UNII	88755TAZ87 Y
KEGG	D07567 Y
ChEBI	CHEBI:356416 Y
ChEMBL	CHEMBL601 Y
Chemical data
Formula	C5H9NO3
Molecular mass	131.13 g/mol
SMILES O=C(CN)CCC(=O)O
InChI InChI=1S/C5H9NO3/c6-3-4(7)1-2-5(8)9/h1-3,6H2,(H,8,9) Y Key:ZGXJTSGNIOSYLO-UHFFFAOYSA-N Y
Physical data
Melting point	118 °C (244 °F)
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δ-Aminolevulinic acid (dALA or δ-ALA or 5ala or 5-aminolevulinic acid ) is the first compound in the porphyrin synthesis pathway, the pathway that leads to heme in mammals and chlorophyll in plants.

In plants, production of δ-ALA is the step on which the speed of synthesis of chlorophyll is regulated. Plants that are fed by external δ-ALA accumulate toxic amounts of chlorophyll precursor, protochlorophyllide, indicating that the synthesis of this intermediate is not suppressed anywhere downwards in the chain of reaction. Protochlorophyllide is a strong photosensitizer in plants.

Biosynthesis

In non-photosynthetic eukaryotes such as animals, insects, fungi, and protozoa, as well as the Alphaproteobacteria class of bacteria, it is produced by the enzyme ALA synthase, from glycine and succinyl CoA. This reaction is known as the Shemin pathway, which occurs in mitochondria.

In plants, algae, bacteria (except for the α-proteobacteria group) and archaea, it is produced from glutamic acid via glutamyl-tRNA and glutamate-1-semialdehyde. The enzymes involved in this pathway are glutamyl-tRNA synthetase, glutamyl-tRNA reductase, and glutamate-1-semialdehyde 2,1-aminomutase. This pathway is known as the C5 or Beale pathway. In most plastid-containing species, glutamyl-tRNA is encoded by a plastid gene, and the transcription, as well as the following steps of C5 pathway, take place in plastids.

Clinical significance

It elicits synthesis and accumulation of fluorescent porphyrins (protoporphyrin IX) in epithelia and neoplastic tissues, among them malignant gliomas. It is used to visualise tumorous tissue in neurosurgical procedures. Studies have shown that the intraoperative use of this guiding method may reduce the tumour residual volume and prolong progression-free survival in patients suffering from this disease.

Being a precursor of photosensitizer, aminolevulinic acid is also a used as an agent for photodynamic therapy.

Cancer diagnosis

Photodynamic detection is the use of photosensitive drugs with a light source of the right wavelength for the detection of cancer, using fluorescence of the drug.

5-Aminolevulinic acid can be used to visualize bladder cancer.

Cancer treatment

Photodynamic therapy (PDT) treatment possibilities include those for cancer of the prostate, breast, giant BCC (skin), cervix, recurrent bladder, vulvar, brain (human glioblastoma cells), HPV, lung, stomach, head and neck, penis, and colon, as well as those for leukemia, Barrett's esophagus, squamous cell carcinoma (SCC), Bowen's disease, and other types of cancer.

See also

• Porphyrin