What is the difference between Sodium D-Aspartic Acid and regular D-Aspartic acid?

[MickyMacgraw]

As above ^

[anneasquith]

sodium is saline........salt.

[MickyMacgraw]

So taking salt with D-aspartic acid would be turned to Sodium D-Aspartic Acid in my body?

[jomifl]

Quite often lists of contents are ambiguous as they may say aspartic acid but they really mean the aspartic part of the sodium (or other )salt as the sodium part of the salt is inactive with regard to the reason for using the aspartic acid or salt.
Sodium is not sal,t it is a metal. Sodium chloride is common salt.

[theprof]

I'm fascinated. D-Aspartic acid sodium salt monohydrate? Try buying that at Sigma-Aldrich!

[theprof]

MickyMacgraw. Taking salt with D-aspartic acid will not turn it into sodium D-Aspartic acid, whatever that is.

jomifl, yes indeed the listing of chemical compounds in a preparation can be ambiguous. Nevertheless, there are strict guidelines in place that would not allow such a situation as you mention arising. In this case, they would have to disclose that aspartic acid is present in the form of sodium aspartate ie "aspartic acid (as sodium aspartate) x%".

In no sense is it true true that the sodium part of the salt is inactive. Sodium is not inactive in the body and the total mmol of the sodium in products can make an immense difference to those on low-sodium diets for example.

The guidelines are there to prevent ambiguity. Any company marketing a product without adhering to these guidelines faces a heavy fine and removal of the product off the market by the FSA in the UK, who are compelled to follow European regulations on these matters.

[pcbpage]

...but to answer your question, sodium aspartate is the sodium salt of aspartic acid. Treatment with acid, for example in your stomach, will regenerate aspartic acid.

[jomifl]

Prof ..I meant that sodium ions do not contribute to the sweetening effect.

[theprof]

jomifl, what sweetening effect? Sodium D-Aspartic acid is not considered sweet. Besides, looking through the posts, i can't find a single reference to sweetness.

[theprof]

pcbpage, it's not that simple. Sodium aspartate is not converted to D-aspartic acid by stomach acid. Furthermore, I'm afraid that "regenerate" is a term that is not recognised in chemical reactions.If you're implying that this is some form of reversible reaction, I'm afraid that that is incorrect as well.

[jomifl]

Prof.. I must read things more carefully...for some reason I had aspartame in mind very silly of me. :-(

[pcbpage]

well, theprof, treating the mono or disodium salt of D-aspartic acid with HCl will certainly produce D-aspartic acid or even the ammonium salt, and this certainly is an equilibrium process. pH in the stomach is say 1 to 3. The pKa of aspartic acid is around 4 I believe; that of HCl is estimated even as low as -7. Racemization of aspartic acid is presumably unlikely in the stomach, so the proteinogenic L-aspartic acid will not be produced. I guess this is what you mean.

[theprof]

Exactly, pcbpage. Racemisation of the D enantiomer is impossible in the stomach as it depends on a number of conditions being met. Whilst the pKa of HCl is one factor, the greatest hurdle against racemisation is fluctuations in body temperature. Furthermore, conversion at 37 degrees C or thereabouts is problematical in itself as the temperature is far too low for effective racemisation to occur. Remember that living creatures selectively utilise only the L enantiomers of the amino acids in enzymes, effectively forming a state of disequilibrium. D-Asp is virtually useless in the body and in general , is only to found in mammalian metabolically inert tissues.

Paradoxically, as the L enantiomers are racemised to the D form after death, their presence can be useful to forensic scientists, marine biologists and paleobiologists etc for amino acid dating.

Incidentally, the exact pKa of HCl is unknown as it’s calculated using thermodynamic data rather than measurement. It’s said to be anything between -4 and -9 depending on the source. This is also of some relevance as far as racemisation is concerned.

[MickyMacgraw]

Thank you for your help everyone.
(Better the prof!) :)