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MetaCyc Enzyme: tetrahydrofolate synthase

Gene: folC Accession Number: G-3721 (MetaCyc)

Synonyms: folylpoly-γ-glutamate synthetase

Species: Corynebacterium sp.

Subunit composition of tetrahydrofolate synthase = [FolC]
         folylpoly-γ-synthetase subunit = FolC

Summary:
The purified enzyme catalyzed a MgATP-dependent addition of glutamate to a variety of reduced pteroate and reduced pteroylmono-, di-, and triglutamate substrates with the concomitant production of ADP and Pi [Shane80]. There are several differences between this enzyme and the enzyme frpm Escherichia coli: The Escherichia coli enzyme utilizes 10-formyl-H4PteGlu (10-formyl-tetrahydrofolate) more effectively than H4PteGlu (tetrahydrofolate), and can not utilize 5-formyl-H4PteGlu. The Corynebacterium enzyme, on the other hand, can effectively use the substrates tetrahydrofolate, 5,10-methylene-tetrahydrofolate, dihydropteroate, and tetrahydropteroate at low concentrations. Pteroate and pteroylmonoglutamate substrates were utilized much more effectively than the polyglutamate derivatives. The most effective substrates were tetrahydropteroate, tetrahydrofolate, and 5,10-methylene-tetrahydrofolate. The most effective diglutamate substrate was 5,10-methylene-tetrahydropteroyldiglutamate. Addition of more than one glutamate moiety was only observed with tetrahydropteroate and 5,10-methylene-tetrahydropteroylmono- and diglutamates as substrates [Shane80].
Although the enzyme eluted from a Sephadex G-150 column primarily as a monomer, in the presence of high K + the elution profile is skewed toward high molecular weight. Because of the enzymatic requirement for K+, together with the requirement for bovine serum albumin with low enzyme concentrations, the authors speculate that the active form of the enzyme is a dimer [Shane80].

Molecular Weight of Polypeptide: 53 kD (experimental) [Shane80 ]

Unification Links: ModBase:Q8NN38 , Protein Model Portal:Q8NN38 , Swiss-Model:Q8NN38 , UniProt:Q8NN38

Relationship Links: Entrez-Nucleotide:PART-OF:BX927155 , InterPro:IN-FAMILY:IPR001645 , InterPro:IN-FAMILY:IPR004101 , InterPro:IN-FAMILY:IPR013221 , InterPro:IN-FAMILY:IPR018109 , Panther:IN-FAMILY:PTHR11136 , Pfam:IN-FAMILY:PF02875 , Pfam:IN-FAMILY:PF08245 , Prosite:IN-FAMILY:PS01012

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

Instance reactions of [tetrahydropteroyl-[γ-Glu](n) + L-glutamate + ATP → tetrahydropteroyl-[γ-Glu](n+1) + ADP + phosphate] (6.3.2.17):
i1: 10-formyl-tetrahydropteroyl-[γ-Glu](n) + L-glutamate + ATP → 10-formyl-tetrahydropteroyl-[γ-Glu](n+1) + ADP + phosphate (6.3.2.17)

i2: methylene-tetrahydropteroyl-[γ-Glu](n) + L-glutamate + ATP → methylene-tetrahydropteroyl-[γ-Glu](n+1) + ADP + phosphate (6.3.2.17)

i3: an N5-formyl-tetrahydrofolate + L-glutamate + ATP = 5-formyl-THF-Glun+1 + ADP + phosphate (no EC#)

MultiFun Terms: metabolism biosynthesis of building blocks cofactors, small molecule carriers folic acid


Enzymatic reaction of: tetrahydropteroyl-γ-polyglutamate:L-glutamate γ-ligase (ADP-forming) (tetrahydrofolate synthase)

EC Number: 6.3.2.17

tetrahydropteroyl-[γ-Glu](n) + L-glutamate + ATP <=> tetrahydropteroyl-[γ-Glu](n+1) + ADP + phosphate

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

The reaction is physiologically favored in the direction shown.

In Pathways: folate polyglutamylation

Activators (Unknown Mechanism): K+ [Shane80] , Mg2+ [Shane80]

pH(opt): 10 [Shane80]


Enzymatic reaction of: 5,10-methylene-tetrahydrofolate:L-glutamate γ-ligase (ADP-forming) (tetrahydrofolate synthase)

EC Number: 6.3.2.17

methylene-tetrahydropteroyl-[γ-Glu](n) + L-glutamate + ATP <=> methylene-tetrahydropteroyl-[γ-Glu](n+1) + ADP + phosphate

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

The reaction is physiologically favored in the direction shown.

In Pathways: folate polyglutamylation

Summary:
methylene-tetrahydrofolate is an alternative substrate for tetrahydrofolate


Enzymatic reaction of: N10-formyl-tetrahydrofolate:L-glutamate γ-ligase (ADP-forming) (tetrahydrofolate synthase)

EC Number: 6.3.2.17

10-formyl-tetrahydropteroyl-[γ-Glu](n) + L-glutamate + ATP <=> 10-formyl-tetrahydropteroyl-[γ-Glu](n+1) + ADP + phosphate

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

The reaction is physiologically favored in the direction shown.

In Pathways: folate polyglutamylation

Summary:
10-formyl-tetrahydrofolate is an alternative substrate for tetrahydrofolate

Activators (Unknown Mechanism): K+ [Shane80] , Mg2+ [Shane80]


References

Shane80: Shane B (1980). "Pteroylpoly(gamma-glutamate) synthesis by Corynebacterium species. Purification and properties of folypoly(gamma-glutamate) synthetase." J Biol Chem 255(12);5655-62. PMID: 6892912


Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by SRI International Pathway Tools version 19.0 on Sat Mar 28, 2015, biocyc13.