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Scientists discover essential step in recharging the eye's light-sensing retina (Cysteine & Vitamin A)
Medical Xpress / National Institutes of Health / Life Science Alliance ^ | Oct. 26, 2022 | Sheetal Uppal et al

Posted on 10/27/2022 8:19:02 AM PDT by ConservativeMind

Scientists have discovered a mechanism by which an area of a protein shape-shifts to convert vitamin A into a form usable by the eye's light-sensing photoreceptor cells. A previously uncharacterized area of the protein known as RPE65 spontaneously turns spiral-shaped when it encounters intracellular membranes, or thin structures that surround different parts of a cell.

This shapeshifting enables RPE65 to enter the endoplasmic reticulum—a network of sac-like structures and tubes—where RPE65 performs the crucial task of vitamin A conversion.

Vision occurs when light hits photoreceptor pigments called opsins, triggering a series of chemical reactions that generate signals to the brain. The retinal pigment epithelium (RPE), a support tissue next to the photoreceptors, recharges opsins to restore their sensitivity to light. In a process known as the visual cycle, RPE65 is essential to convert the spent vitamin A derivative all-trans retinol, back into photosensitive 11-cis retinal. Mutations in the RPE65 gene are associated with early-onset severe blinding disorders.

Interaction of RPE65 with the RPE cell's endoplasmic reticulum is essential to making 11-cis retinal, but the mechanism by which RPE65 binds to the endoplasmic reticulum membrane was until now a mystery.

The NEI team discovered that in aqueous solution, a specific region of RPE65 lacks structure, but when it encounters membranes, it spontaneously forms an amphipathic alpha-helix—a special sort of spiral shape in proteins. This change enables RPE65 it to bind to the RPE cells' endoplasmic reticulum membrane where 11-cis retinal is produced from all-trans retinol.

More than that, when a single specific amino acid within the previously uncharacterized region of RPE65 was modified by a specific lipid, it greatly expedited the formation of the alpha-helix, "locking" it into place, and facilitating its insertion into the cell membrane. This was something never seen before in a protein, according to Uppal.

(Excerpt) Read more at medicalxpress.com ...


TOPICS: Health/Medicine
KEYWORDS: glynac
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The abstract describes the “single specific amino acid” as being cysteine, which we can get from food and was believed to also be readily made by our bodies, but recently was found to be restricted in its creation by aging.

Other amino acids we stop properly making include glycine and taurine. Together, supplementing these three amino acids has been found to allow our bodies to again make glutathione and superoxide dismutase (SOD), the two key antioxidants we have plenty of, as children.

These studies were previously posted here on Free Republic under “GlyNAC” and “Taurine” in the titles and keywords.

The form of Vitamin A in the essential step is a heavily converted form our bodies make from Vitamin A.

1 posted on 10/27/2022 8:19:02 AM PDT by ConservativeMind
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To: Mazey; ckilmer; goodnesswins; Jane Long; BusterDog; jy8z; ProtectOurFreedom; matthew fuller; ...

The “Take Charge Of Your Health” Ping List

This high volume ping list is for health articles and studies which describe something you or your doctor, when informed, may be able to immediately implement for your benefit.

Email me to get on either the “Common/Top Issues” (20 - 25% fewer pings) or “Everything” list.

2 posted on 10/27/2022 8:19:45 AM PDT by ConservativeMind (Trump: Befuddling Democrats, Republicans, and the Media for the benefit of the US and all mankind.)
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To: ConservativeMind

So carrots are good for eyesight after all. Bugs Bunny was right.


3 posted on 10/27/2022 8:25:30 AM PDT by noiseman (The only thing necessary for the triumph of evil is for good men to do nothing.)
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To: ConservativeMind

Please add me to the health ping list if possible......thx.


4 posted on 10/27/2022 8:28:27 AM PDT by Liz (MAN PROPOSES.......... GOD DISPOSES )
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To: noiseman
So carrots are good for eyesight after all.

If that is so, why are there so many dead bunnies on the road?

5 posted on 10/27/2022 8:29:38 AM PDT by spankalib
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To: ConservativeMind

And yet we are supposed to believe all these mechanisms are just an accident of evolution, without a Creator to guide the processes from the very beginning..........................


6 posted on 10/27/2022 8:32:05 AM PDT by Red Badger (Homeless veterans camp in the streets while illegal aliens are put up in hotels.....................)
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To: ConservativeMind

symbiotic shapeshifters


7 posted on 10/27/2022 8:37:35 AM PDT by DannyTN
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To: ConservativeMind

I recently started taking two grams each of glycine and nac —three times a day.

This combination has significantly increased my feeling of health and well being

I’ve not read of any upper limits for the safe intake of glycine much below 10 grams daily

However, the literature generally limits the safe intake of NAC to only 2 grams daily. However, the only study on unsafe NAC limits I’ve seen were at about 10 grams daily and that was outlier.

Have you read about any safe upper limits to NAC daily intake.


8 posted on 10/27/2022 8:38:02 AM PDT by ckilmer (q)
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To: ConservativeMind

Appreciate the data streams.


9 posted on 10/27/2022 8:40:41 AM PDT by MHGinTN (A dispensation perspective is a powerful tool for discernment)
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To: spankalib
Those are squirrels, you need to get your eyes checked.

10 posted on 10/27/2022 8:41:41 AM PDT by Waverunner
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To: ConservativeMind

your comment is the first I’ve read of superoxide dismutase (SOD).

do taurine and cysteine individually increase SOD or do they work together like gly/nac work together to increase glutathione

Can you post more on that.

I did not know that our cysteine and taurine levels decline with age.

How much cystein and taurine do you recommend as a daily supplements.

Glutathione levels drop with age. But also auto immune and chronic diseases as well as high bmi push glutathione levels lower.

Have you seen that these diseases also lower cystein and taurine levels—and therefor SOD— beyond what aging does?


11 posted on 10/27/2022 8:47:06 AM PDT by ckilmer (q)
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To: ConservativeMind
Other amino acids we stop properly making include glycine and taurine.

I've been taking 3,000 mg of Taurine a day for many years now. I believe it's improved my vision.

12 posted on 10/27/2022 9:27:54 AM PDT by Angelino97
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To: ckilmer
I would take smaller doses more frequently. Whatever can't be immediately used to make glutathione or SOD is used elsewhere in one-off amino acid situations, which can be good, but can be bad. For instance, some cancers love cysteine. If, instead, you take equal amounts of glycine with cysteine (NAC), your body preferentially converts it to the much needed glutathione, while other processes (including cancer) get just residual, more normal, amounts, as I've read. Do note we still make a little cysteine and get some from food, but no longer enough for our total needed processes. Glutathione lasts just a few hours in our cells before it's used up.

Too much glycine, by itself, can make people pretty drowsy. Too much NAC, by itself, without a direct, known, bodily need hasn't been generally tested in people for much beyond a handful of weeks, in my readings. So acute ingestion of glycine and chronically high amounts of NAC appear to have concerns not well fleshed out, in my thinking.

Do note, however, the two GlyNAC studies were done on 70-80 year old people, and their ingestion rates were at or above 7,000 mg (7 grams) for each of glycine and NAC, but seemingly done periodically through the day, as they most noted the glutathione results causing so much good, with secondary results from excess glycine and cysteine. How do you get the most glutathione into your body's cells each day? Take a lot of smaller doses of GlyNAC, spaced a few hours apart.

13 posted on 10/27/2022 9:51:21 AM PDT by ConservativeMind (Trump: Befuddling Democrats, Republicans, and the Media for the benefit of the US and all mankind.)
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To: spankalib

“If that is so, why are there so many dead bunnies on the road?”

LOL?


14 posted on 10/27/2022 9:56:13 AM PDT by dljordan
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To: spankalib

The bunnies were hit by pickup trucks. Crows give warnings for caws but can’t say pickup truck.


15 posted on 10/27/2022 10:03:12 AM PDT by Cold Heart (Everybody vaxxed was injured, your degree of damage and timing may differ)
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To: ckilmer

You’ve read my study posts on these. Taurine is the missing step for SOD creation and glycine and NAC make glutathione, for older people.

Adding back these amino acids lets the body again produce the glutathione and SOD our bodies lack as we age, creating ongoing inflammation that creates all sorts of formal “old age” health problems. The processes are still there, but show they are starved of key ingredients we once provided in abundance.

GlyNAC alone reverses a bunch of negative blood, brain, and even physical function indicators. When 80 year olds, in their standard walking gait, go from much slower walkers than 30 year olds to faster than the 30 year old walkers, something pretty amazing has happened.

I know I’ve stated these points in prior threads I’ve pinged you on.


16 posted on 10/27/2022 10:15:33 AM PDT by ConservativeMind (Trump: Befuddling Democrats, Republicans, and the Media for the benefit of the US and all mankind.)
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To: ConservativeMind

How much taurine do you take. One of the guys above said he took 3 grams daily. (he thinks it improves his eyesight as per the article)

I’m currently taking 500mg daily.

What do you recommend? What daily upper limits have you seen.


17 posted on 10/27/2022 10:39:09 AM PDT by ckilmer (q)
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To: ckilmer

We take the amount mentioned in the study, and sometimes a bit more.

https://freerepublic.com/focus/f-chat/4080060/posts


18 posted on 10/27/2022 10:46:02 AM PDT by ConservativeMind (Trump: Befuddling Democrats, Republicans, and the Media for the benefit of the US and all mankind.)
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To: Cold Heart

Those are the New England crows?


19 posted on 10/27/2022 12:31:09 PM PDT by telescope115 (Proud member of the ANTIFAuci movement. )
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To: ConservativeMind

I’ve been taking taurine at 1-2 grams a day. i’m moving that up to 3 grams daily at intervals


20 posted on 10/27/2022 1:32:37 PM PDT by ckilmer (q)
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