Posted by Larry Hoover on July 24, 2004, at 11:21:14
In reply to Questions about Phenylalanine and more., posted by Indie on July 24, 2004, at 10:13:53
> I am wondering about the differences between a few supplements.
You've come to the right place.
> 1) Is there a difference between L-Phenylalanine and DL-Phenylalanine? If so, what is it?For many molecules with biological activity, there are different ways they can be put together, and still be the same thing. The D- and L- (also shown as R-/S- or +/-) designations refer to a pair of otherwise identical molecules, which differ in being mirror images of each other, like a pair of gloves are mirror images of each other. And like a pair of gloves, the individual molecules are not absolutely interchangeable. You can't put a right hand in a left glove, even though it still retains all the properties of gloves in general.
Each individual form of the matched molecules is called an enantiomer. There's the D- enantiomer, and the L-enantiomer. Mother Nature has, by an evolutionary flip of the coin, stuck to using L- enantiomers of the amino acids, under nearly all circumstances. So, L-phenylalanine is the "natural" enantiomer, and is almost entirely the form you get in food.
When you see an amino acid labeled as DL, it means there's a roughly 50% mix of both enantiomers. That's called a racemic mixture, and it usually means that the substance was man-made. Unlike Mother Nature, which has enzymes structured to favour L-aminos, chemists and their reaction vessels don't have control over how the last bits go together. Random chance leads to there being about 50% of both forms.
Some D-aminos are toxic. They may contribute to the toxicity of some bacterial by-products. Most are innocuous, or give opportunities not often obtained from food. (The aminos in beer are roughly 10% D-enantiomers, so maybe there's something special about beer, after all.) With respect to D-phenylalanine, it promotes formation of a feel-good chemical called PEA, and also blocks the breakdown of other feel-good chemicals. It helps in pain control, for example.
> 2) What is the difference between taking Glutamic Acid and Glutamine?Glutamine is glutamic acid with an extra amine functional group. I bet that didn't mean much to you, but they are interchangeable by enzymatic transformation, and they have opposite effects, one to the other. (The very same thing applies to the two forms of vitamin B3, with nicotinic acid and nicotinamide having diametrically opposite effects at some receptors).
Simply put, glutamic acid is excitatory, whereas glutamine is inhibitory, but sometimes the glutamic acid excites an inhibitory process (net inhibitory effect), and sometimes the glutamine inhibits an inhibitory process (net excitatory effect), so the outcomes can seem paradoxical. Like amphetamine to treat hyperactivity. It works, but it doesn't seem logical, on its face.
MSG is the sodium salt of glutamic acid.
> 3) What is the difference between taking L-tryptophan and 5--HTP?
The synthesis of serotonin from tryptophan goes in steps. The first step is to change tryptophan into 5-hydroxytryptophan (5-HTP). 5-HTP is called an intermediate. The next conversion is 5-HTP to 5-hydroxytryptamine (5-HT), which is also known as serotonin. (If you ever see in medical literature references like "the 5-HT1a receptor", they're talking about family 1 type a serotonin receptors.)
The enzyme that converts tryptophan to 5-HTP is only found in tissues which use serotonin. That first step conversion is called the rate-limiting step, because the rate of synthesis is slower and more controlled than the second step. Your body controls the amount of total serotonin by regulating this step (when everything is working as it should). The enzyme that converts 5-HTP to serotonin is found everywhere, all over the body, even in tissues that are not normally exposed to (much) serotonin. If you take oral 5-HTP, your whole system is, in essence, exposed to serotonin, in a completely unregulated way....not just the brain. If you take tryptophan, your body's regulatory system of enzymes is not by-passed. More raw materials for the enzyme (tryptophan) generally translates into more product (5-HTP), but only in the tissues which are designed for serotonin function (e.g. the brain). The step that converts 5-HTP to serotonin is virtually instantaneous (1/1,000,000,000 of a second). I think it's better, in general, to help your body do what it's designed to do (process tryptophan) than to consume an intermediate (5-HTP) that has unnatural effects.
> Any info would be really helpful.
>
> Thanks,
> IndieMore questions welcomed.
Lar
poster:Larry Hoover
thread:369909
URL: http://www.dr-bob.org/babble/alter/20040718/msgs/369926.html