Biology:Glycine dehydrogenase (decarboxylating)

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Short description: Protein-coding gene in the species Homo sapiens


A representation of the 3D structure of the protein myoglobin showing turquoise α-helices.
Generic protein structure example
glycine decarboxylase
Identifiers
EC number1.4.4.2
CAS number37259-67-9
Databases
IntEnzIntEnz view
BRENDABRENDA entry
ExPASyNiceZyme view
KEGGKEGG entry
MetaCycmetabolic pathway
PRIAMprofile
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO

Glycine decarboxylase also known as glycine cleavage system P protein or glycine dehydrogenase is an enzyme that in humans is encoded by the GLDC gene.[1][2][3]

Reaction

Glycine decarboxylase (EC 1.4.4.2) is an enzyme that catalyzes the following chemical reaction:

glycine + H-protein-lipoyllysine [math]\displaystyle{ \rightleftharpoons }[/math] H-protein-S-aminomethyldihydrolipoyllysine + CO2

Thus, the two substrates of this enzyme are glycine and H-protein-lipoyllysine, whereas its two products are H-protein-S-aminomethyldihydrolipoyllysine and CO2.[4]

This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-NH2 group of donors with a disulfide as acceptor. This enzyme participates in glycine, serine and threonine metabolism. It employs one cofactor, pyridoxal phosphate.

Function

Glycine decarboxylase is the P-protein of the glycine cleavage system in eukaryotes. The glycine cleavage system catalyzes the degradation of glycine. The P protein binds the alpha-amino group of glycine through its pyridoxal phosphate cofactor. Carbon dioxide is released and the remaining methylamine moiety is then transferred to the lipoamide cofactor of the H protein.

Degradation of glycine is brought about by the glycine cleavage system, which is composed of four mitochondrial protein components: P protein (a pyridoxal phosphate-dependent glycine decarboxylase), H protein (a lipoic acid-containing protein), T protein (a tetrahydrofolate-requiring enzyme), and L protein (a lipoamide dehydrogenase).[3]

Clinical significance

Glycine encephalopathy is due to defects in GLDC or AMT of the glycine cleavage system.[3]

References

  1. "The glycine cleavage system. Molecular cloning of the chicken and human glycine decarboxylase cDNAs and some characteristics involved in the deduced protein structures". J Biol Chem 266 (5): 3323–9. Mar 1991. doi:10.1016/S0021-9258(18)49991-7. PMID 1993704. 
  2. "Structural and expression analyses of normal and mutant mRNA encoding glycine decarboxylase: three-base deletion in mRNA causes nonketotic hyperglycinemia". Biochem Biophys Res Commun 174 (3): 1176–82. Mar 1991. doi:10.1016/0006-291X(91)91545-N. PMID 1996985. 
  3. 3.0 3.1 3.2 "Entrez Gene: GLDC glycine dehydrogenase (decarboxylating)". https://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=2731. 
  4. Kikuchi G (2008). "The glycine cleavage system: reaction mechanism, physiological significance, and hyperglycinemia". Proc. Jpn. Acad. Ser. B Phys. Biol. Sci. 84 (7): 246–63. doi:10.2183/pjab.84.246. PMID 18941301. Bibcode2008PJAB...84..246K. 

Further reading