Target type: biologicalprocess
The chemical reactions and pathways involving hypoxanthine, 6-hydroxy purine, an intermediate in the degradation of adenylate. Its ribonucleoside is known as inosine and its ribonucleotide as inosinate. [GOC:go_curators]
Hypoxanthine metabolism is a crucial process within the purine nucleotide cycle, responsible for the breakdown and salvage of purine bases, particularly hypoxanthine. It plays a vital role in maintaining cellular energy levels, DNA synthesis, and overall nucleotide homeostasis. The process involves several key enzymatic steps:
1. **Hypoxanthine Phosphoribosyltransferase (HPRT)**: This enzyme catalyzes the conversion of hypoxanthine into inosine monophosphate (IMP), a crucial intermediate in purine nucleotide biosynthesis. This reaction utilizes phosphoribosyl pyrophosphate (PRPP) as a substrate, transferring the phosphoribosyl moiety from PRPP to hypoxanthine.
2. **IMP Dehydrogenase (IMPDH)**: Inosine monophosphate dehydrogenase catalyzes the NAD-dependent oxidation of IMP to xanthine monophosphate (XMP), a precursor for guanine nucleotide biosynthesis. This step is essential for the production of GMP, a building block for DNA and RNA.
3. **Xanthine Oxidase (XO)**: This enzyme, along with the related xanthine dehydrogenase, catalyzes the oxidation of hypoxanthine to xanthine and further to uric acid. This reaction is crucial for the degradation of purine bases, preventing their accumulation to toxic levels within the body.
4. **Uric Acid Excretion**: Uric acid, the final product of purine metabolism, is primarily excreted through the kidneys. However, in certain conditions like gout, uric acid accumulates in the blood and joints, leading to inflammation and pain.
Hypoxanthine metabolism is tightly regulated to maintain the balance between purine synthesis and degradation. This regulation is essential for cellular function and overall organismal health. Disruptions in this process can lead to various metabolic disorders, including gout, Lesch-Nyhan syndrome, and immunodeficiency.'
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| Protein | Definition | Taxonomy |
|---|---|---|
| Hypoxanthine-guanine phosphoribosyltransferase | A hypoxanthine-guanine phosphoribosyltransferase that is encoded in the genome of human. [PRO:DNx, UniProtKB:P00492] | Homo sapiens (human) |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| chrysene | chrysene : An ortho-fused polycyclic arene found commonly in the coal tar. chrysene: structure in Merck Index, 9th ed, #2252 | ortho-fused polycyclic arene | plant metabolite |
| 6-chrysenamine | 6-chrysenamine: may cause splenic atrophy and leukopenia; minor descriptor (76-84); on-line & Index Medicus search PHENANTHRENES (76-84) | carbopolycyclic compound | |
| 6-nitrochrysene | 6-nitrochrysene: RN given refers to cpd with locant for nitro group in position 6 | carbopolycyclic compound | |
| mercaptopurine | mercaptopurine : A member of the class of purines that is 6,7-dihydro-1H-purine carrying a thione group at position 6. An adenine analogue, it is used in the treatment of acute lymphocytic leukemia (ALL), chronic myeloid leukemia (CML), Crohn's disease, and ulcerative colitis. Mercaptopurine: An antimetabolite antineoplastic agent with immunosuppressant properties. It interferes with nucleic acid synthesis by inhibiting purine metabolism and is used, usually in combination with other drugs, in the treatment of or in remission maintenance programs for leukemia. purine-6-thiol : A thiol that is the tautomer of mercaptopurine. | aryl thiol; purines; thiocarbonyl compound | anticoronaviral agent; antimetabolite; antineoplastic agent |
| thioguanine anhydrous | Thioguanine: An antineoplastic compound which also has antimetabolite action. The drug is used in the therapy of acute leukemia. tioguanine : A 2-aminopurine that is the 6-thiono derivative of 2-amino-1,9-dihydro-6H-purine. Incorporates into DNA and inhibits synthesis. Used in the treatment of leukaemia. | 2-aminopurines | anticoronaviral agent; antimetabolite; antineoplastic agent |
| guanosine monophosphate | guanosine 5'-monophosphate : A purine ribonucleoside 5'-monophosphate having guanine as the nucleobase. Guanosine Monophosphate: A guanine nucleotide containing one phosphate group esterified to the sugar moiety and found widely in nature. | guanosine 5'-phosphate; purine ribonucleoside 5'-monophosphate | biomarker; Escherichia coli metabolite; metabolite; mouse metabolite |
| guanine | 2-aminopurines; oxopurine; purine nucleobase | algal metabolite; Escherichia coli metabolite; human metabolite; mouse metabolite; Saccharomyces cerevisiae metabolite | |
| hypoxanthine | nucleobase analogue; oxopurine; purine nucleobase | fundamental metabolite | |
| inosinic acid | Inosine Monophosphate: Inosine 5'-Monophosphate. A purine nucleotide which has hypoxanthine as the base and one phosphate group esterified to the sugar moiety. | inosine phosphate; purine ribonucleoside 5'-monophosphate | Escherichia coli metabolite; human metabolite; mouse metabolite |
| allopurinol | allopurinol : A bicyclic structure comprising a pyrazole ring fused to a hydroxy-substituted pyrimidine ring. Allopurinol: A XANTHINE OXIDASE inhibitor that decreases URIC ACID production. It also acts as an antimetabolite on some simpler organisms. | nucleobase analogue; organic heterobicyclic compound | antimetabolite; EC 1.17.3.2 (xanthine oxidase) inhibitor; gout suppressant; radical scavenger |
| azaguanine | 8-azaguanine : A triazolopyrimidine that consists of 3,6-dihydro-7H-[1,2,3]triazolo[4,5-d]pyrimidine bearing amino and oxo substituents at positions 5 and 7 respectively. Azaguanine: One of the early purine analogs showing antineoplastic activity. It functions as an antimetabolite and is easily incorporated into ribonucleic acids. | nucleobase analogue; triazolopyrimidines | antimetabolite; antineoplastic agent; EC 2.4.2.1 (purine-nucleoside phosphorylase) inhibitor |