ホスホリボシルピロリン酸シンテターゼ。
EC 2.7.6.1
ATPのβ位およびγ位のリン酸をD-リボース5-リン酸の一位に転移し、ホスホリボシル２リン酸（PRPP）を生成する反応を触媒する。
D-リボース5-リン酸 + ATP (dATP) ---> PRPP + AMP (dAMP)
ペントースリン酸回路とヌクレオチド合成経路の分岐点に位置し、プリンおよびピリミジンヌクレオチド合成に律速的役割を果たすアロステリック酵素である。ADP、GDPは阻害され、ピリミジンヌクレオチドが抑制的制御をする。
Ribose-phosphate pyrophosphokinase 2
EC=2.7.6.1
Alternative name(s):
PPRibP
Phosphoribosyl pyrophosphate synthase II
Short name=PRS-II
- Function
- Catalyzes the synthesis of phosphoribosylpyrophosphate (PRPP) that is essential for nucleotide synthesis. HAMAP-Rule MF_00583_B
- Catalytic activity
- ATP + D-ribose 5-phosphate = AMP + 5-phospho-alpha-D-ribose 1-diphosphate. HAMAP-Rule MF_00583_B
- Cofactor
- Magnesium.
- Enzyme regulation
- Activated by magnesium and inorganic phosphate. Competitively or non-competitively inhibited by ADP, 2,3-bisphosphoglyceride or GDP. HAMAP-Rule MF_00583_B
- Pathway
- Metabolic intermediate biosynthesis; 5-phospho-alpha-D-ribose 1-diphosphate biosynthesis; 5-phospho-alpha-D-ribose 1-diphosphate from D-ribose 5-phosphate (route I): step 1/1. HAMAP-Rule MF_00583_B
- Subunit structure
- Homodimer. The active form is probably a hexamer composed of 3 homodimers
Ribose-phosphate pyrophosphokinase 1
EC=2.7.6.1
Alternative name(s):
PPRibP
Phosphoribosyl pyrophosphate synthase I
Short name=PRS-I
Involvement in disease
- Phosphoribosylpyrophosphate synthetase superactivity (PRPS1 superactivity) [MIM
- 300661]: Familial disorder characterized by excessive purine production, gout and uric acid urolithiasis.
- Note: The disease is caused by mutations affecting the gene represented in this entry.
- Charcot-Marie-Tooth disease, X-linked recessive, 5 (CMTX5) [MIM
- 311070]: A form of Charcot-Marie-Tooth disease, a disorder of the peripheral nervous system, characterized by progressive weakness and atrophy, initially of the peroneal muscles and later of the distal muscles of the arms. Charcot-Marie-Tooth disease is classified in two main groups on the basis of electrophysiologic properties and histopathology: primary peripheral demyelinating neuropathies characterized by severely reduced motor nerve conduction velocities (NCVs) (less than 38m/s) and segmental demyelination and remyelination, and primary peripheral axonal neuropathies characterized by normal or mildly reduced NCVs and chronic axonal degeneration and regeneration on nerve biopsy.
Note: The disease is caused by mutations affecting the gene represented in this entry. Ref.16
- ARTS syndrome (ARTS) [MIM
- 301835]: A disorder characterized by mental retardation, early-onset hypotonia, ataxia, delayed motor development, hearing impairment, and optic atrophy. Susceptibility to infections, especially of the upper respiratory tract, can result in early death.
Note: The disease is caused by mutations affecting the gene represented in this entry. Ref.15
- Deafness, X-linked, 1 (DFNX1) [MIM
- 304500]: A form of deafness characterized by progressive, severe-to-profound sensorineural hearing loss in males. Females manifest mild to moderate hearing loss.
Note: The disease is caused by mutations affecting the gene represented in this entry.
