Foolihapon THB sukulaisvitamiini tetrahydrobiopteriini THB ( BH4)

En saata olla tässä maintsematta, että  vaikka ihmiskeho ei pysty syntetisoimaan foolihappoa, niin kuitenkin sukulaisainetta tetrahydrobiopteriinia pitäisi kehossa muodostua ja sen lähtömolekyyli on GTP.
 https://www.researchgate.net/profile/Patrick_Mchugh4/publication/42639606/figure/fig3/AS:280428566073382@1443870788631/Figure-1-Tetrahydrobiopterin-biosynthesis-pathways-in-the-body-The-biosynthesis-of-BH4.png





GTP-rengas  tarvitsee syklohydrolaasin ja silloin muodostuu  toinen rengastuma puriini sijaan. muodostuu dihydroneopteriini. Se muokataan sepiapteriiniksi ja siitä taas tehdään THB,
THB, 5,6,7,8- tetrahydrobiopteriini, jota  esim  hermosolut tarvitsevat  ottamaan vastaan yksittäistä happea.. tällä on toinen nimi BH4.  Sitä tarvitaan koentsyyminä  aroamtatisille aminohapoille,
Minkälainen entsyymi on sepiapteriini reduktaasi ?
 https://en.wikipedia.org/wiki/Sepiapterin_reductase

THB ja  THF eivät ole kaukana toistensa  rakenteesta, mutta ne eivät muutu toisikseen ja niillä on omat vaiktutusalueet.  Joitain samoja entyymejäkin ne käyttävät.

 Folaatti auttaakin aika pitkälle ihmistä keskushermoston alueella. mutta se ei voi auttaa sitä aluetta missä toimii vain kehosyntyinen  BH4, Tetrahydrobiopteriini.

Olen pohtinut voisiko kehovitamiinia BH4, jollaint avalla  saada kehoon koska se on ihmisen korkeimman kognition  alueella toimiva, dopamiinihermoissa, joka on kognitiivinen takasäätöjärjestelmä.  sekä aromaattisten aminohappojen aineenvaihdunnassa, josta  hermonvälittäjäaineita muodsotuu.

 Tästä on aika vähän tietoa  tavallisessa  lehdistössä, joka muuten puhuu vitamiinesita paljon.  BH4 ei ole käsitelty NNR.ssä tai en ole huomannut sitä käsitellyn. Se on fundamentaaliaineenvaihduntaa, mutta silti vitamiininomainen.

SPR geeni on kromosomissa 2p13.2. ja se koodaa entsyymiä, joka katalysoi pteridiinijohdannaisia NADPH.sta riippuvsti  ja auttaa BH4 muodostusta. 

Related articles in PubMed

1. Sepiapterin Reductase Deficiency Friedman J, et al. , 1993. PMID 26131547
2. Clinical and genetic studies in a family with a novel mutation in the sepiapterin reductase gene. Koht J, et al. Acta Neurol Scand Suppl, 2014. PMID 24588500
3. A homozygous frameshift mutation of sepiapterin reductase gene causing parkinsonism with onset in childhood. Lohmann E, et al. Parkinsonism Relat Disord, 2012 Feb. PMID 22018912
4. Role of sepiapterin reductase gene at the PARK3 locus in Parkinson's disease. Sharma M, et al. Neurobiol Aging, 2011 Nov. PMID 21782285
5. Sleep and rhythm consequences of a genetically induced loss of serotonin. Leu-Semenescu S, et al. Sleep, 2010 Mar. PMID 20337188, Free PMC Article

See all (43) citations in PubMed

See citations in PubMed for homologs of this gene provided by HomoloGene

GeneRIFs: Gene References Into FunctionsWhat's a GeneRIF?

1. The allele frequencies for the SPR c.596-2A > G (0.7%) polymorphism is not a major cause of Parkinson's disease in the Maltese.
2. We earlier presented evidence for a physical interaction between ODC and SPR and we showed that RNAi-mediated knockdown of SPR expression significantly reduced native ODC enzyme activity and impeded Neuroblastoma cell proliferation.
3. new homozygous mutation in the SPR gene was found in two sisters with dopa-responsive dystonia
4. Authors identified SPR as a novel regulator of ODC enzyme activity and, based on clinical evidence, present a model in which SPR drives ODC-mediated malignant progression in neuroblastoma.
5. SPR-mediated reduction of sepiapterin and redox cycling occur by distinct mechanisms
6. SRD can manifest as early-onset parkinsonism, widening the spectrum of the disease phenotype and adding to the genetic heterogeneity of the disease
7. this large association study for the SPR gene revealed no association for Parkinson disease worldwide.

Neurobiol Aging. 2011 Nov;32(11):2108.e1-5. doi: 10.1016/j.neurobiolaging.2011.05.024. Epub 2011 Jul 22.

Role of sepiapterin reductase gene at the PARK3 locus in Parkinson's disease.

Sharma M¹, Maraganore DM,  et al.

Sepiapterin reductase (SPR) gene is an enzyme which catalyses the final step of tetrahydrobiopterin synthesis (BH4) and was implicated in Parkinson's disease (PD) pathogenesis as a candidate gene for PARK3 locus. A number of studies yielded association of the PARK3 locus with PD, and SPR knockout mice were shown to display parkinsonian features. To evaluate the role of SPR gene polymorphisms in diverse populations in PD, we performed collaborative analyses in the Genetic Epidemiology of Parkinson Disease (GEO-PD) Consortium. A total of 5 single nucleotide polymorphisms (3 in the promoter region and 2 in the 3' untranslated region [UTR]) were genotyped. Fixed as well as random effect models were used to provide summary risk estimates of SPR variants. A total of 19 sites provided data for 6547 cases and 9321 controls. Overall odds ratio estimates varied from 0.92 to 1.01. No overall association with the SPR gene using either fixed effect or random effect model was observed in the studied population. I(2) Metric varied from 0% to 36.2%. There was some evidence for an association for participants of North European/Scandinavian descent with the strongest signal for rs1876487 (odds ratio = 0.82; p value = 0.003). Interestingly, families which were used to map the PARK3 locus, have Scandinavian ancestry suggesting a founder effect. In conclusion, this large association study for the SPR gene revealed no association for PD worldwide. However, taking the initial mapping of the PARK3 into account, the role of a population-specific effect warrants consideration in future studies.

1. We examine the sleep, sleep-wake rhythms, CSF neurotransmitters, and melatonin profile in a patient with sepiapterin reductase deficiency.
2. Observational study, meta-analysis, and genome-wide association study of gene-disease association. (HuGE Navigator)
3. Observational study of gene-disease association and gene-gene interaction. (HuGE Navigator)

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  Löydän FASS- luettelosta Sapropterin molekyylin.
Se on THB stereoisomeeri.
Siis sitä tyyppiä  on olemassa- mutta kehossa sen pitäisi muodostua  esim neuronin sisäisesti.
Sitä nöytetään käytettään  kohdissa missaä BH4 on koentsyymi  aminohappojen  metaboliassa.
DA-neuronissa taas on kyse  BH4  de novo synteesistä.   paikallisen happiradikaalimaailman  antioksidantiksi välimuotoja ovat kinoidit.