gtp cyclohydrolase การใช้

• Not all patients show mutations in the GCH1 gene ( GTP cyclohydrolase I ), which makes genetic testing imperfect.
• Mutations in this gene are associated with malignant phenylketonuria ( PKU ) and hyperphenylalaninemia ( HPA ), as well as GTP cyclohydrolase I deficiency.
• The dominant form, with mutation in only one of the two alleles for GTP cyclohydrolase I, causes dopamine-responsive dystonia, characterized by childhood-onset dystonia.
• In the different types of the gene therapy, the investigations are encoding enzymes that are necessary for dopamine synthesis, such as tyrosine hydroxylase, GTP cyclohydrolase 1 and AADC.
• Deficiency of GTP cyclohydrolase I can occur in a recessive and in a dominant form and lead to a lack of certain neurotrasmitters ( dopamine, norepinephrine, epinephrine and serotonin ).
• It is formed from GTP by the enzyme GTP cyclohydrolase IIa which catalyzes the hydrolysis of the 8, 9 bond in the guanine group and loss of the beta and gamma phosphate groups.
• Patients with the recessive form have mutations in both alleles for GTP cyclohydrolase I . Patients present with developmental delays and neurological dysfunction with trunk hypotonia, hypertonia of the extremities, abnormal movements, tremors, convulsions, and sometimes autonomic dysfunction.
• Sometimes a lumbar puncture is performed to measure concentrations of biopterin and neopterin, which can help determine the exact form of dopamine-responsive movement disorder : early onset parkinsonism ( reduced biopterin and normal neopterin ), GTP cyclohydrolase I deficiency ( both decreased ) and tyrosine hydroxylase deficiency ( both normal ).
• "' 2, 5-diamino-6-hydroxy-4-( 5-phosphoribosylamino ) pyrimidine "'is a metabolite in the purine metabolism, formed by the hydrolysis of GTP by GTP cyclohydrolase II . Alternatively two separate enzymes can carry out this reaction, initially GTP cyclohydrolase IIa hydrolyses the 8, 9 bond to form 2-Amino-5-formylamino-6-( 5-phospho-D-ribosylamino ) pyrimidin-4 ( 3H )-one, followed by de-formylation by 2-amino-5-formylamino-6-ribosylaminopyrimidin-4 ( 3H )-one 5'- monophosphate deformylase . 2, 5-diamino-6-hydroxy-4-( 5-phosphoribosylamino ) pyrimidine is deaminated by Diaminohydroxyphosphoribosylaminopyrimidine deaminase to form 5-amino-6-( 5-phosphoribosylamino ) uracil.
• "' 2, 5-diamino-6-hydroxy-4-( 5-phosphoribosylamino ) pyrimidine "'is a metabolite in the purine metabolism, formed by the hydrolysis of GTP by GTP cyclohydrolase II . Alternatively two separate enzymes can carry out this reaction, initially GTP cyclohydrolase IIa hydrolyses the 8, 9 bond to form 2-Amino-5-formylamino-6-( 5-phospho-D-ribosylamino ) pyrimidin-4 ( 3H )-one, followed by de-formylation by 2-amino-5-formylamino-6-ribosylaminopyrimidin-4 ( 3H )-one 5'- monophosphate deformylase . 2, 5-diamino-6-hydroxy-4-( 5-phosphoribosylamino ) pyrimidine is deaminated by Diaminohydroxyphosphoribosylaminopyrimidine deaminase to form 5-amino-6-( 5-phosphoribosylamino ) uracil.