Human Gene MTAP (ENST00000580900.5) Description and Page Index
Description: Catalyzes the reversible phosphorylation of S-methyl-5'- thioadenosine (MTA) to adenine and 5-methylthioribose-1-phosphate. Involved in the breakdown of MTA, a major by-product of polyamine biosynthesis. Responsible for the first step in the methionine salvage pathway after MTA has been generated from S- adenosylmethionine. Has broad substrate specificity with 6- aminopurine nucleosides as preferred substrates. (from UniProt Q13126) Gencode Transcript: ENST00000580900.5 Gencode Gene: ENSG00000099810.21 Transcript (Including UTRs) Position: hg38 chr9:21,802,649-21,937,651 Size: 135,003 Total Exon Count: 8 Strand: + Coding Region Position: hg38 chr9:21,802,749-21,931,199 Size: 128,451 Coding Exon Count: 8
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Comments and Description Text from UniProtKB
ID:MTAP_HUMAN DESCRIPTION: RecName: Full=S-methyl-5'-thioadenosine phosphorylase; EC=2.4.2.28; AltName: Full=5'-methylthioadenosine phosphorylase; Short=MTA phosphorylase; Short=MTAP; Short=MTAPase; FUNCTION: Catalyzes the reversible phosphorylation of S-methyl-5'- thioadenosine (MTA) to adenine and 5-methylthioribose-1-phosphate. Involved in the breakdown of MTA, a major by-product of polyamine biosynthesis. Responsible for the first step in the methionine salvage pathway after MTA has been generated from S- adenosylmethionine. Has broad substrate specificity with 6- aminopurine nucleosides as preferred substrates. CATALYTIC ACTIVITY: S-methyl-5'-thioadenosine + phosphate = adenine + S-methyl-5-thio-alpha-D-ribose 1-phosphate. ENZYME REGULATION: Inhibited by 5'-methylthiotubercin and 5'- chloroformycin. BIOPHYSICOCHEMICAL PROPERTIES: Kinetic parameters: KM=5 uM for S-methyl-5'-thioadenosine; KM=580 uM for phosphate; KM=23 uM for adenine; KM=8 uM for S-methyl-5-thio-alpha-D-ribose 1-phosphate; pH dependence: Optimum pH is 7.2-7.6; PATHWAY: Amino-acid biosynthesis; L-methionine biosynthesis via salvage pathway; S-methyl-5-thio-alpha-D-ribose 1-phosphate from S-methyl-5'-thioadenosine (phosphorylase route): step 1/1. SUBUNIT: Homotrimer. SUBCELLULAR LOCATION: Cytoplasm. Nucleus (By similarity). TISSUE SPECIFICITY: Ubiquitously expressed. DISEASE: Defects in MTAP are the cause of diaphyseal medullary stenosis with malignant fibrous histiocytoma (DMSMFH) [MIM:112250]. An autosomal dominant bone dysplasia characterized by pathologic fractures due to abnormal cortical growth and diaphyseal medullary stenosis. The fractures heal poorly, and there is progressive bowing of the lower extremities. Some patients show a limb-girdle myopathy, with muscle weakness and atrophy. Approximately 35% of affected individuals develop an aggressive form of bone sarcoma consistent with malignant fibrous histiocytoma or osteosarcoma. Note=DMSMFH causing mutations found in MTAP exon 9 result in exon skipping and dysregulated alternative splicing of all MTAP isoforms (PubMed:22464254). DISEASE: Note=Loss of MTAP activity may play a role in human cancer. MTAP loss has been reported in a number of cancers, including osteosarcoma, malignant melanoma and gastric cancer. SIMILARITY: Belongs to the PNP/MTAP phosphorylase family. MTAP subfamily.
ModBase Predicted Comparative 3D Structure on Q13126
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Other Names for This Gene
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Methods, Credits, and Use Restrictions
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