Page last updated: 2024-10-24

IMP cyclohydrolase activity

Definition

Target type: molecularfunction

Catalysis of the reaction: IMP + H2O = 5-formamido-1-(5-phosphoribosyl)imidazole-4-carboxamide. [EC:3.5.4.10]

IMP cyclohydrolase activity is a key enzymatic reaction in the purine nucleotide biosynthesis pathway. It catalyzes the conversion of inosine monophosphate (IMP) to 5-amino-4-imidazolecarboxamide ribonucleotide (AICAR). This conversion is essential for the synthesis of both adenine and guanine nucleotides. IMP cyclohydrolase utilizes a single molecule of water to hydrolyze the carbon-nitrogen bond at the 6 position of the purine ring in IMP. This hydrolysis reaction requires a divalent metal cation such as magnesium or manganese for optimal activity. The enzyme first binds to IMP, forming a stable enzyme-substrate complex. This complex then undergoes a conformational change that positions the water molecule for attack on the carbon-nitrogen bond. This attack results in the cleavage of the bond and the release of AICAR. The AICAR molecule then serves as a precursor for the synthesis of both AMP and GMP. Therefore, IMP cyclohydrolase plays a critical role in maintaining cellular purine nucleotide pools, which are essential for various cellular processes including DNA replication, RNA transcription, and protein synthesis.'
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Proteins (1)

ProteinDefinitionTaxonomy
Bifunctional purine biosynthesis protein ATICA bifunctional purine biosynthesis protein ATIC that is encoded in the genome of human. [PRO:DNx, UniProtKB:P31939]Homo sapiens (human)

Compounds (9)

CompoundDefinitionClassesRoles
sulfasalazinesulfasalazine : An azobenzene consisting of diphenyldiazene having a carboxy substituent at the 4-position, a hydroxy substituent at the 3-position and a 2-pyridylaminosulphonyl substituent at the 4'-position.

Sulfasalazine: A drug that is used in the management of inflammatory bowel diseases. Its activity is generally considered to lie in its metabolic breakdown product, 5-aminosalicylic acid (see MESALAMINE) released in the colon. (From Martindale, The Extra Pharmacopoeia, 30th ed, p907)
veratridinesteroidsodium channel modulator
aica ribonucleotideAICA ribonucleotide : A 1-(phosphoribosyl)imidazolecarboxamide that is acadesine in which the hydroxy group at the 5' position has been converted to its monophosphate derivative.

AICA ribonucleotide: purine precursor that has antineoplastic activity
1-(phosphoribosyl)imidazolecarboxamide;
aminoimidazole
cardiovascular drug;
Escherichia coli metabolite;
human metabolite;
mouse metabolite;
plant metabolite;
Saccharomyces cerevisiae metabolite
methotrexatedicarboxylic acid;
monocarboxylic acid amide;
pteridines
abortifacient;
antimetabolite;
antineoplastic agent;
antirheumatic drug;
dermatologic drug;
DNA synthesis inhibitor;
EC 1.5.1.3 (dihydrofolate reductase) inhibitor;
immunosuppressive agent
5-formamidoimidazole-4-carboxamide ribotide5-formamidoimidazole-4-carboxamide ribotide: purine precursor1-(phosphoribosyl)imidazolecarboxamideEscherichia coli metabolite;
mouse metabolite
nsc 889154-pregnen-21-ol-3,20-dione-21-(4-bromobenzenesufonate): a tyrosyl-DNA phosphodiesterase inhibitor; structure in first source
5,11-methenyltetrahydrohomofolate
pemetrexedpemetrexed disodium : An organic sodium salt that is the disodium salt of N-{4-[2-(2-amino-4-oxo-4,7-dihydro-1H-pyrrolo[2,3-d]pyrimidin-5-yl)ethyl]benzoyl}-L-glutamic acid. Inhibits thymidylate synthase (TS), 421 dihydrofolate reductase (DHFR), and glycinamide ribonucleotide formyltransferase (GARFT).N-acyl-L-glutamic acid;
pyrrolopyrimidine
antimetabolite;
antineoplastic agent;
EC 1.5.1.3 (dihydrofolate reductase) inhibitor;
EC 2.1.1.45 (thymidylate synthase) inhibitor;
EC 2.1.2.2 (phosphoribosylglycinamide formyltransferase) inhibitor
lometrexollometrexol: RN & structure given in first source;