Thiopurine methyltransferase

Last updated

TPMT
Protein TPMT PDB 2bzg.png
Available structures
PDB Ortholog search: PDBe RCSB
Identifiers
Aliases TPMT , entrez:7172, TPMTD, thiopurine S-methyltransferase
External IDs OMIM: 187680; MGI: 98812; HomoloGene: 313; GeneCards: TPMT; OMA:TPMT - orthologs
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_000367
NM_001346817
NM_001346818

NM_016785

RefSeq (protein)

NP_000358
NP_001333746
NP_001333747

NP_058065

Location (UCSC) Chr 6: 18.13 – 18.16 Mb Chr 13: 47.18 – 47.2 Mb
PubMed search [3] [4]
Wikidata
View/Edit Human View/Edit Mouse

Thiopurine methyltransferase or thiopurine S-methyltransferase (TPMT) is an enzyme that in humans is encoded by the TPMT gene. A pseudogene for this locus is located on chromosome 18q. [5] [6]

Contents

Thiopurine methyltransferase Thiopurine methyltransferase.png
Thiopurine methyltransferase

Function

thiopurine S-methyltransferase
Identifiers
EC no. 2.1.1.67
CAS no. 67339-09-7
Databases
IntEnz IntEnz view
BRENDA BRENDA entry
ExPASy NiceZyme view
KEGG KEGG entry
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Gene Ontology AmiGO / QuickGO
Search
PMC articles
PubMed articles
NCBI proteins

Thiopurine methyltransferase methylates thiopurine compounds. The methyl donor is S-adenosyl-L-methionine, which is converted to S-adenosyl-L-homocysteine. This enzyme metabolizes thiopurine drugs via S-adenosyl-L-methionine as the S-methyl donor and S-adenosyl-L-homocysteine as a byproduct. [5] [7]

Clinical significance

Thiopurine drugs such as 6-mercaptopurine are used as chemotherapeutic agents and immunosuppressive drugs. Genetic polymorphisms that affect this enzyme's activity are correlated with variations in sensitivity and toxicity to such drugs. About 1/300 individual is deficient for the enzyme. [5]

Pharmacology

TPMT is best known for its role in the metabolism of the thiopurine drugs such as azathioprine, 6-mercaptopurine and 6-thioguanine. TPMT catalyzes the S-methylation of thiopurine drugs. Defects in the TPMT gene leads to decreased methylation and decreased inactivation of 6MP leading to enhanced bone marrow toxicity which may cause myelosuppression, anemia, bleeding tendency, leukopenia & infection. [8] [9] [10] Allopurinol inhibits thiopurine S-methyltransferase, which can increase the utility of 6-MP. [11]

Diagnostic use

Measurement of TPMT activity is encouraged prior to commencing the treatment of patients with thiopurine drugs such as azathioprine, 6-mercaptopurine and 6-thioguanine. Patients with low activity (10% prevalence) or especially absent activity (prevalence 0.3%) are at a heightened risk of drug-induced bone marrow toxicity due to accumulation of the unmetabolised drug. Reuther et al. found that about 5% of all thiopurine therapies will fail due to toxicity. This intolerant group could be anticipated by routine measurement of TPMT activity. There appears to be a great deal of variation in TPMT mutation, with ethnic differences in mutation types accounting for variable responses to 6MP. [9] [12]

Genetic variants of TPMT have also been associated with cisplatin-induced ototoxicity in children. [13] TPMT is now listed as a pharmacogenomic biomarker for adverse drug reactions to cisplatin by the FDA. [14]

See also

Related Research Articles

<span class="mw-page-title-main">Allopurinol</span> Medication

Allopurinol is a medication used to decrease high blood uric acid levels. It is specifically used to prevent gout, prevent specific types of kidney stones and for the high uric acid levels that can occur with chemotherapy. It is taken orally or intravenously.

<span class="mw-page-title-main">Azathioprine</span> Immunosuppressive medication

Azathioprine, sold under the brand name Imuran, among others, is an immunosuppressive medication. It is used for the treatment of rheumatoid arthritis, granulomatosis with polyangiitis, Crohn's disease, ulcerative colitis, and systemic lupus erythematosus; and in kidney transplants to prevent rejection. It is listed by the International Agency for Research on Cancer as a group 1 human carcinogen. It is taken by mouth or injected into a vein.

<span class="mw-page-title-main">Single-nucleotide polymorphism</span> Single nucleotide in genomic DNA at which different sequence alternatives exist

In genetics and bioinformatics, a single-nucleotide polymorphism is a germline substitution of a single nucleotide at a specific position in the genome. Although certain definitions require the substitution to be present in a sufficiently large fraction of the population, many publications do not apply such a frequency threshold.

Catechol-<i>O</i>-methyltransferase Class of enzymes

Catechol-O-methyltransferase is one of several enzymes that degrade catecholamines, catecholestrogens, and various drugs and substances having a catechol structure. In humans, catechol-O-methyltransferase protein is encoded by the COMT gene. Two isoforms of COMT are produced: the soluble short form (S-COMT) and the membrane bound long form (MB-COMT). As the regulation of catecholamines is impaired in a number of medical conditions, several pharmaceutical drugs target COMT to alter its activity and therefore the availability of catecholamines. COMT was first discovered by the biochemist Julius Axelrod in 1957.

<span class="mw-page-title-main">Pharmacogenomics</span> Study of the role of the genome in drug response

Pharmacogenomics, often abbreviated "PGx," is the study of the role of the genome in drug response. Its name reflects its combining of pharmacology and genomics. Pharmacogenomics analyzes how the genetic makeup of a patient affects their response to drugs. It deals with the influence of acquired and inherited genetic variation on drug response, by correlating DNA mutations with pharmacokinetic, pharmacodynamic, and/or immunogenic endpoints.

<span class="mw-page-title-main">Mercaptopurine</span> Chemical compound

Mercaptopurine (6-MP), sold under the brand name Purinethol among others, is a medication used for cancer and autoimmune diseases. Specifically it is used to treat acute lymphocytic leukemia (ALL), acute promyelocytic leukemia (APL), Crohn's disease, and ulcerative colitis. For acute lymphocytic leukemia it is generally used with methotrexate. It is taken orally.

<span class="mw-page-title-main">N-acetyltransferase</span> Class of enzymes

N-acetyltransferase (NAT) is an enzyme that catalyzes the transfer of acetyl groups from acetyl-CoA to arylamines, arylhydroxylamines and arylhydrazines. They have wide specificity for aromatic amines, particularly serotonin, and can also catalyze acetyl transfer between arylamines without CoA. N-acetyltransferases are cytosolic enzymes found in the liver and many tissues of most mammalian species, except the dog and fox, which cannot acetylate xenobiotics.

<span class="mw-page-title-main">Tioguanine</span> Chemical compound

Tioguanine, also known as thioguanine or 6-thioguanine (6-TG) or tabloid is a medication used to treat acute myeloid leukemia (AML), acute lymphocytic leukemia (ALL), and chronic myeloid leukemia (CML). Long-term use is not recommended. It is given by mouth.

Histamine <i>N</i>-methyltransferase Mammalian enzyme involved in the metabolism of histamine

Histamine N-methyltransferase (HNMT) is a protein encoded by the HNMT gene in humans. It belongs to the methyltransferases superfamily of enzymes and plays a role in the inactivation of histamine, a biomolecule that is involved in various physiological processes. Methyltransferases are present in every life form including archaeans, with 230 families of methyltransferases found across species.

<span class="mw-page-title-main">Thiopurine</span> Class of chemical compounds

The thiopurine drugs are purine antimetabolites widely used in the treatment of acute lymphoblastic leukemia, autoimmune disorders, and organ transplant recipients.

<span class="mw-page-title-main">NNMT</span> Protein-coding gene in humans

Nicotinamide N-methyltransferase (NNMT) is an enzyme that in humans is encoded by the NNMT gene. NNMT catalyzes the methylation of nicotinamide and similar compounds using the methyl donor S-adenosyl methionine (SAM-e) to produce S-adenosyl-L-homocysteine (SAH) and 1-methylnicotinamide.

<span class="mw-page-title-main">AS3MT</span> Protein-coding gene in the species Homo sapiens

Arsenite methyltransferase is an enzyme that in humans is encoded by the AS3MT gene.

<span class="mw-page-title-main">UGT1A5</span> Protein-coding gene in the species Homo sapiens

UDP-glucuronosyltransferase 1-5 is an enzyme that in humans is encoded by the UGT1A5 gene.

<span class="mw-page-title-main">UGT1A9</span> Protein-coding gene in the species Homo sapiens

UDP-glucuronosyltransferase 1-9 is an enzyme that in humans is encoded by the UGT1A9 gene.

<span class="mw-page-title-main">UGT2A1</span> Protein-coding gene in the species Homo sapiens

UDP glucuronosyltransferase 2 family, polypeptide B1, also known as UGT2B1, is an enzyme that in humans is encoded by the UGT2B1 gene.

<span class="mw-page-title-main">Aldehyde oxidase 1</span> Protein-coding gene in the species Homo sapiens

Aldehyde oxidase 1 is an enzyme that in humans is encoded by the AOX1 gene.

<span class="mw-page-title-main">Riin Tamm</span> Estonian geneticist

Riin Tamm is an Estonian geneticist and a proponent of science in popular culture. She is the head of the Department of Youth and Talent Policy within the Estonian Ministry of Education and Research. She has previously served as the director of University of Tartu Youth Academy.

<span class="mw-page-title-main">NUDT15</span>

Nudix hydrolase 15 is a protein that in humans is encoded by the NUDT15 gene.

<span class="mw-page-title-main">Cancer pharmacogenomics</span>

Cancer pharmacogenomics is the study of how variances in the genome influences an individual’s response to different cancer drug treatments. It is a subset of the broader field of pharmacogenomics, which is the area of study aimed at understanding how genetic variants influence drug efficacy and toxicity.

Howard L. McLeod is an American pharmacogeneticist and implementation scientist specialized in precision medicine.

References

  1. 1 2 3 GRCh38: Ensembl release 89: ENSG00000137364 Ensembl, May 2017
  2. 1 2 3 GRCm38: Ensembl release 89: ENSMUSG00000021376 Ensembl, May 2017
  3. "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. 1 2 3 "Entrez Gene: TPMT thiopurine S-methyltransferase". National Center for Biotechnology Information . Retrieved 2012-07-02.
  6. Lee D, Szumlanski C, Houtman J, Honchel R, Rojas K, Overhauser J, Wieben ED, Weinshilboum RM (March 1995). "Thiopurine methyltransferase pharmacogenetics. Cloning of human liver cDNA and a processed pseudogene on human chromosome 18q21.1". Drug Metab. Dispos. 23 (3): 398–405. PMID   7628307.
  7. Weinshilboum RM, Sladek SL (1980). "Mercaptopurine pharmacogenetics: Monogenic inheritance of erythrocyte thiopurine methyltransferase activity". American Journal of Human Genetics. 32 (5): 651–662. PMC   1686086 . PMID   7191632.
  8. Fujita K, Sasaki Y (August 2007). "Pharmacogenomics in drug-metabolizing enzymes catalyzing anticancer drugs for personalized cancer chemotherapy". Curr. Drug Metab. 8 (6): 554–62. doi:10.2174/138920007781368890. PMID   17691917. Archived from the original on 2013-01-12. Retrieved 2008-07-25.{{cite journal}}: CS1 maint: unfit URL (link)
  9. 1 2 Oncea I, Duley J (2008). "Chapter 38: Pharmacogenetics of Thiopurines". Goodman & Gilman's The Pharmacological Basis of Therapeutics (11th ed.). McGraw-Hill's Access Medicine.
  10. Evans WE. (2004). "Pharmacogenetics of thiopurine S-methyltransferase and thiopurine therapy". Ther Drug Monit. 26 (2): 186–91. doi:10.1097/00007691-200404000-00018. PMID   15228163. S2CID   34015182.
  11. "The Mechanism and Drug Interaction - Allopurinol and Azathioprine and Risk of Bone Marrow Suppression". www.ebmconsult.com. Retrieved 2019-03-24.
  12. Genome Bioinformatics Group, Center for Biomolecular Science and Engineering. "Human Gene TPMT (uc003ncm.1)". UCSC Genome Browser. University of California Santa Cruz. Retrieved 2008-07-25.
  13. Ross CJ, Katzov-Eckert H, Dubé MP, Brooks B, Rassekh SR, Barhdadi A, Feroz-Zada Y, Visscher H, Brown AM, Rieder MJ, Rogers PC, Phillips MS, Carleton BC, Hayden MR (December 2009). "Genetic variants in TPMT and COMT are associated with hearing loss in children receiving cisplatin chemotherapy". Nat. Genet. 41 (12): 1345–9. doi:10.1038/ng.478. PMID   19898482. S2CID   21293339.
  14. "Cisplatin". Science & Research (Drugs). United States Food and Drug Administration.

Further reading