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Topic: Hg and sulphhydral groups: A layman's question.  (Read 19019 times)

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Offline cut_to_the_quick

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Hg and sulphhydral groups: A layman's question.
« on: July 30, 2008, 11:59:31 AM »
Hello!  I am NOT a chemist, but I am writing a review for a video called Autism: Misdiagnosis of Future Generations and I have a biochem or organic chem question. 

The part of the video that I found most compelling was the same part my wife (an osteopathic physician) found most suspect.  She said I should seek the advice of someone in the biochem field. 

In the video, Rashid A. Buttar, DO makes the following  assertions concerning mercury in the body and chelation therapy to remove mercury:

Hg binds to sulphhydral groups.

Hg binds to the sulphhydral group at the terminal end (tail) of the protein and   inside the body of the protein.

Chelating only effects the Hg on the terminal structure of the protein and does not effect the Hg attached to the sulphhydral groups on the inside of the protein structure.

When the Hg on the tail is removed via chelating, the Hg in the body of the protein will dissipate and move to the tail where it can be removed by another round of chelation therapy.  Therefore, over time, the concentration of Hg inside the protein is reduced by chelation therapy.  Dr. Buttar likens this a drop of ink in water; remove ink from one part of the water and the overall concentration of the ink is reduced as the ink dissipates.   

My question is this:  Is the ink-in-water metaphor valid?  Will Hg really have a tendency to “move” from the sulphhydral groups within the protein to the sulphhydral group at the terminal end of the protein?

If you have no idea, I would appreciate the reader printing my question and taking it to a university professor or industry professional who might. 

About me:  I am an accountant and father of a boy with autism.  I review materials on the subject of autism to help other parents (especially parents who need to make every penny count) determine which materials are based in science and which ones are based on unsound assertions or anecdote.  You assistance and expertise are appreciated.

--Matthew

Offline macman104

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Re: Hg and sulphhydral groups: A layman's question.
« Reply #1 on: July 30, 2008, 12:33:48 PM »
The analogy that if you remove some "solute" from a solution the rest will dissapate to make a uniform solution again, and thus overall more dilute seems to make sense.  I don't know anything about whether the Hg will actually move though.

However, googling Rashid Buttar does not provide many favorable results praising his integrity and practices, so I'd caution yourself.

Offline cut_to_the_quick

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Re: Hg and sulphhydral groups: A layman's question.
« Reply #2 on: July 30, 2008, 01:00:58 PM »
Thanks for your reply.  Don't worry, I think this guy is a quack and he is currently facing unprofessional conduct charges by the North Carolina Board of Medicine.  My child will never go near one of his clinics.

Your reply helps solidify my question, though.  Is the entire protein one solution, or are the tail and the body separate solutions?  If the former is true, then yes removing solute from one part of the protein would cause that solute to seek equilibrium throughout the solution. 

For some reason I can't put my finger on, my gut tells me that these are separate solutions; Hg bound to the internal sulphhydral groups will not move to the terminal sulphhydral group. 

Matthew

Offline macman104

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Re: Hg and sulphhydral groups: A layman's question.
« Reply #3 on: July 30, 2008, 01:07:09 PM »
Thanks for your reply.  Don't worry, I think this guy is a quack and he is currently facing unprofessional conduct charges by the North Carolina Board of Medicine.  My child will never go near one of his clinics.

Your reply helps solidify my question, though.  Is the entire protein one solution, or are the tail and the body separate solutions?  If the former is true, then yes removing solute from one part of the protein would cause that solute to seek equilibrium throughout the solution. 

For some reason I can't put my finger on, my gut tells me that these are separate solutions; Hg bound to the internal sulphhydral groups will not move to the terminal sulphhydral group.
Unfortunately, my biochemical knowledge is quite limited.  There are quite a few biologists and biochemists on these forums, hopefully one of them can address the biochemical aspect of the claims.

Offline azmanam

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Re: Hg and sulphhydral groups: A layman's question.
« Reply #4 on: July 30, 2008, 01:28:35 PM »
I think it is plausible that the mercury will migrate to terminal sulfhydryl groups.  I am also not a biochemist, but protein binding equilibria are just that: equilibria.  With respective equilibrium constants.  If the binding is stronger to the terminal sulfhydryl groups (larger binding constant), those will be populated by mercury first, then the ones on the interior of the protein.  Chelation might not be able to reach the internal mercury due to crowding issues (sterics), thus chelation can only remove the more easily-accessible mercury bound to the terminal sulfhydryl group.  This disrupts the equilibrium, and the mixture re-equilibrates - moving the mercury to the sulfhydryl with the stronger binding constant, i.e. the terminal one.  This continues until the mercury is removed.

That being said, I don't know what protein we're dealing with, and I don't know what the binding constants are, or even what chelator is being used (is it EDTA?), so I cannot make any claims with certainty.

Given all that, my wife is in graduate school and has been studying autism since undergrad, and she is highly skeptical of the mercury-autism link.  She is essentially convinced mercury is not culpable as a cause of autism: http://www.reuters.com/article/healthNews/idUSN0425071020080107.  I wish you the best with your son.
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Offline cut_to_the_quick

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Re: Hg and sulphhydral groups: A layman's question.
« Reply #5 on: July 30, 2008, 01:33:47 PM »
Wow, thanks.  Like your wife, I too am extremely suspect of the heavy metals autism link.  My kids get all their vaccinations, etc. 

The chelating agent is DMPS.  EDTA is used more for lead and arsenic removal, although it does attract some Hg. 

Thanks also for your good wishes.

Matthew

Offline limpet chicken

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Re: Hg and sulphhydral groups: A layman's question.
« Reply #6 on: August 02, 2008, 10:33:22 PM »
Chelation does NOT work, and its considered by most of the autistic community to be a dangerous and barbaric practise, the link suggested by the 'scientist' andrew wakefield was discounted, mercury does NOT cause autism, else for instance, why wasn't  there an outbreak of autism reported when mercury poisoning was responsible for minamata disease?

The vaccine controversy was over a preservative, thiomersal, which metabolised to ethylmercury, organomercurial compounds like methylmercury and ethylmercury are some scary arsed slow, but very lethal neurotoxins in tiny doses, granted in the vaccine its only nanograms to micrograms of EtHg being absorbed, I still don't think it can possibly be justified introducing it to a young child in any dose, especially in this day and age when other preservatives which do not contain Hg are readily available.

This is a subject close to the heart for me, as I'm autistic myself, I view it as quite a positive thing really, it can have a lot of benefits, there is a forum you could  find a great resource, I'm a a member of it, its about making the most of it, which can be quite something :)


WWW.Aspiesforfreedom.com

As I post this , AFF is temporarily unavailable, but its just been down for two days,m it'l be back soon, so check it out, if you check no other autism resource out in ytour life ever, check it out , and tell em Lestat sent yer :)
The light blinds
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Offline Yggdrasil

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Re: Hg and sulphhydral groups: A layman's question.
« Reply #7 on: August 03, 2008, 02:10:24 AM »
Despite being a biochemist, I'll say that my answer is not based on any empirical evidence and just represents my opinion on the matter:

First, I don't think there distinction between the tail end of the protein and the interior of the protein is very good.  Certainly proteins can have thiol (i.e. sulfydryl) groups on the interior or exterior and chelation agents would directly remove mercury from the exterior thiols.  However, the tails of proteins are not necessarily solvent accessible, nor would most proteins necessarily have thiols on their tails.  So, that's the first issue I have.

Second, is the issue of whether elemental mercury can cross plasma membranes.  This is important because proteins on the exterior of cells won't have free thiols.  The extracellular environment is oxidizing, so most thiols on extracellular proteins are involved in disulfide bonds.  In contrast, cells maintain a reducing environment in their interior, so most of the thiols in cytoplasmic proteins are not oxidized and may be free to bind mercury.  Since elemental mercury is nonpolar, I would guess it probably can cross the membrane, but I'm not 100% sure about this.

Third, the ability of chelators to efficiently remove mercury from interior thiols assumes that the affinity for exterior thiols is similar to the affinity for interior thiols.  This may not be true.  The interior of proteins is nonpolar and nonpolar mercury atoms would likely prefer the interior environment over the aqueous exterior environment.  At the same time, the interior of proteins is fairly densely packed, but it is not inconceivable that a small mercury atom (van der waals radius of ~0.15nm compared to the 1-10nm size of most proteins) could fit into the interior of a protein without too much trouble.  If the affinity for interior sites is much greater than exterior sites, it will take a much longer time for chelators to remove these mercury atoms.  If this is the case, a better analogy would be putting a cloth stained with waterproof ink into water.  However, if the affinity of mercury between interior and exterior thiols is similar, the water-ink analogy is perfectly valid.  I would assume one could fairly easily do an experiment to see which situation applies to most proteins.

Offline limpet chicken

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Re: Hg and sulphhydral groups: A layman's question.
« Reply #8 on: August 05, 2008, 01:44:52 PM »
Il repeat, chelation does NOT cure autism, there isn't a shiny new neurotypical person hidden in an autistic shell, autism is WHO WE ARE, and cannot be removed, nor do most of us believe , should it be.
The light blinds
So behold darkness as our new light
In our darkness we can see
So with others blindness
We take flight.

Offline cut_to_the_quick

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Re: Hg and sulphhydral groups: A layman's question.
« Reply #9 on: August 05, 2008, 02:35:57 PM »
Yggdrasil:  Thanks for your response.  This is exactly what my wife (a DO) was thinking, but needed some reassurance and a refresher on the specific terminology of her suspicions.  We appreciate your opinion.

Limpet Chicken:  The people at Defeat Autism Now!* tell me that you autistics are empty shells and soulless beings, devoid of humor and emotion, just waiting for a cure.  Did you not get the memo?   ;)

Now, I came here for a scientific discussion on the chemistry of chelation that I will include on my website (under construction) when I discuss the idiocy of chelation for autistic people.  I had no idea that I would get so many responses criticizing the autism - heavy metals link.  I'm so happy that so many in the study of science are so well informed. 

I am NOT looking for a cure for my son.  He gets some ABA therapy (he's 5 years old) and public school with an IEP.  No sub-q b-12 injections, no GFCF diets, no holding therapy, no chelation  He is extremely echolalic, but I see that as a talent for rote memorization instead of a problem so long as we can teach him to function independently in society. Thanks for your passion.

My review on this video for Amazon can be viewed here: http://www.amazon.com/Know-Your-Options-Misdiagnosis-Generations/dp/B000K14LL8/ref=cm_cr-mr-title

*I'm reviewing a video from these moonbats next

Matthew

Offline limpet chicken

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Re: Hg and sulphhydral groups: A layman's question.
« Reply #10 on: August 19, 2008, 04:53:29 PM »
Oh sorry, I assumed you might be a curebie as soon as I saw 'chelation'.

I got that memo time ago, but being such a soullless oxygen thief, didn't realise there was a 'me' for that to apply to  ;D

Check out aspiesforfreedom, (.com) I think you would be able to find a lot deeper in depth discussion of both biochemistry and the social implications too there :)
The light blinds
So behold darkness as our new light
In our darkness we can see
So with others blindness
We take flight.

Offline cut_to_the_quick

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Re: Hg and sulphhydral groups: A layman's question.
« Reply #11 on: August 24, 2008, 10:15:02 PM »
Quote
didn't realise there was a 'me' for that to apply to

Ha!!  "Curebie" is a new word for me.

It looks like the scientific portion of this discussion has wrapped up, so I probably won't be back until I run across another treatment that seems a little bit  'out there' from a scientific standpoint.  It's nice to know that a layman can post here and be read over 1500 times.  That's a lot of exposure to the scientific community that I really appreciate.  Thanks for having me on your forum.

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