Talk:Tetrahydrobiopterin

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On 24 June 2022, it was proposed that this article be moved to Sapropterin. The result of the discussion was no consensus.

Structural formula

I don't have time to learn how to edit this page right now.

But I noticed the chemical structure of tetrahydrobiopterin is wrong. There are 5 things bonded to the carbon. The correct structure is actually back in the history of this article a few edits ago.... with the N in the ring that's double bonded to the carbonele .... should actually be an NH - single bonded to the carbonele (because it's impossible to have it according to the way the curren png picture shows).

Fixed... it was my careless mistake. Thanks for the notice. solon 11:44, 17 June 2006 (UTC)[reply]

I noticed that the figure actually is for sapropterin, not for tetrahydrobiopterin. Tetrahydrobiopterin should have a protonated nitrogen at the 3 position for the fully reduced form. The nitrogen at the 1 position should actually not be protonated and should have a double bond to the carbon at the 2 position. —Preceding unsigned comment added by 128.197.112.231 (talk) 23:04, 18 March 2008 (UTC)[reply]

The structure given in the file -- showing a proton at N-1 (at the bottom left as drawn) is correct, per Chemical Abstract Service and USAN nomenclature. Sapropterin exists as a tautomer; much of the "tetrahydrobiopterin" literature, historically, has used the alternative tautomer, with the N-3 nitrogen protonated instead of the N-1. Either structure is acceptable. The advantage of using the term "sapropterin" rather than "tetrahydrobiopterin" or "BH4" is simple: by definition, sapropterin means the 6R stereochemistry; tetrahydrobiopterin and BH4 are ambiguous terms. —Preceding unsigned comment added by 64.84.58.84 (talk) 16:35, 6 May 2008 (UTC)[reply]

Also, i have heard this can be used in treating the skin disorder vitiligo, which i suffer from. It has trialled 90% successfully in america and my doctor is now looking to see if i can get it on the NHS —Preceding unsigned comment added by Andyjlaidlaw (talk • contribs) 22:29, 22 July 2010 (UTC)[reply]

Role of BH4 very incomplete, and somewhat inaccurate, as described

I have a genetic disorder on GCH1 which causes a deficiency in BH4 production - I am therefore unfortunately more familiar with BH4 than I'd like to be. As I am not a biochemist, I merely added "citation needed" at the end of the first sentence instead of fixing it - BH4 is not involved in the production of those neurotransmitters, however. Instead of changing current content, I opted for adding additional content (added "other clinical issues").

This entry (and the one about Tetrahydrobiopterin_Deficiency) unfortunately reads like an advertisement for BioMarin and what the FDA has approved Kuvan to be prescribed for; BH4 has many roles that are *exceptionally* more important than treating toxic levels of L-Phenylalanine. That role isn't really a "role" - it's a byproduct of proper biosynthesis of L-Tyrosine which is directly, not indirectly, needed. The vast majority of clinical issues resultant from BH4 deficiency happen long before toxic levels of L-Phenylalanine in the blood, which itself can be alternately treated (as it was, until 2007) by simply lowering the intake of that amino acid - but would still leave a patient with dangerously low levels of L-Dopa and would leave all the other conditions (which are all indirectly caused by the low BH4 levels) still completely untreated. I can avoid L-Phenylalanine in my diet (I don't need to, as my levels aren't high enough to be toxic), but that won't make my dystonia go away. Note that 99% of PKU is not caused by BH4 deficiency, either (Biomarin's own research); one could have PKU and not have any issues with Dopamine levels.

This isn't meant as a harsh to Kuvan/Biomarin; I'd take it if my physician wasn't hesitant to prescribe it in concert with Sinemet. Suggesting BH4 is primarily vital for reduction of L-Phenylalanine levels is very misleading however, in my (admittedly not classically trained) opinion. Taking Kuvan, the drug, is approved primarily for PKU treatment. The two things are not analogous - the FDA doesn't define the deep medical Truths we hope humanity one day discovers.Brianlamere (talk)

There is paper showing that BH4 is a cofactor for NO synthases "The Three Nitric-oxide Synthases Differ in Their Kinetics of Tetrahydrobiopterin Radical Formation, Heme-Dioxy Reduction, and Arginine Hydroxylation*" by Chin-Chuan Wei et al, published in 2005. I've seen papers citing the role as cofactors for the enzymes necessary for making neurotransmitter precursors, but I don't have a copy of it on my computer. I'll post the titles / authors here if I can find them. —Preceding unsigned comment added by 65.47.29.74 (talk) 21:19, 2 May 2011 (UTC)[reply]

Requested move 24 June 2022

The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review after discussing it on the closer's talk page. No further edits should be made to this discussion.

The result of the move request was: no consensus. (closed by non-admin page mover) Vpab15 (talk) 16:50, 18 July 2022 (UTC)[reply]

Tetrahydrobiopterin → Sapropterin – Use the INN for the page name per WP:MEDMOS, WP:PHARMMOS Whywhenwhohow (talk) 20:14, 24 June 2022 (UTC)— Relisting. Usernamekiran (talk) 21:42, 1 July 2022 (UTC) — Relisting. — Ceso femmuin mbolgaig mbung, mellohi! (投稿) 00:53, 10 July 2022 (UTC)[reply]

would support for reasons given above--Ozzie10aaaa (talk) 19:29, 4 July 2022 (UTC)[reply]
Oppose - It looks to me like Sapropterin (trade name Kuvan) is a synthetic form of the natural cofactor still referred to as tetrahydrobiopterin (here and here for two). This article largely describes the role of the natural cofactor, which to me takes precedence to the INN referring to the synthetic form used as a drug. I was somewhat surprised to see the suggestion, and have learned something from reading it, as I have not come across the word Sapropterin despite looking after patients with pterin-related movement disorders. |→ Spaully ^~talk~ 20:07, 4 July 2022 (UTC)[reply]

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.