Phosphomethylpyrimidine synthase

Phosphomethylpyrimidine synthase (EC 4.1.99.17, thiC (gene)) is an enzyme with systematic name 5-amino-1-(5-phospho-D-ribosyl)imidazole formate-lyase (decarboxylating, 4-amino-2-methyl-5-phosphomethylpyrimidine-forming).^[1][2][3] This enzyme catalyses the following chemical reaction

5-amino-1-(5-phospho-D-ribosyl)imidazole + S-adenosyl-L-methionine ${\displaystyle \rightleftharpoons }$ 4-amino-2-methyl-5-phosphomethylpyrimidine + 5′-deoxyadenosine + L-methionine + formate + CO

Phosphomethylpyrimidine synthase
Phosphomethylpyrimidine synthase dimer, Arabidopsis thaliana
Identifiers
EC no.	4.1.99.17
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Search PMC articles PubMed articles NCBI proteins

This enzyme binds a 4Fe-4S cluster.

The starting material is 5-aminoimidazole ribotide, which undergoes a rearrangement reaction via radical intermediates which incorporate the blue, green and red fragments shown into the product.^[3][4]