phonypapercut wrote...
Sources for information like D-aspartate being likely to bond with sodium for it to be soluble?
This is not entirely necessary during the urea production, but certainly when it would be excreted through liquids, where the D-Aspartate residue would have to be somewhate soluble, the most readily available chemical would be sodium (at first, I'd wrongly assumed the only way would be forming a dipeptide with D-Phenylalanine, resulting in Aspartame, as you'd noticed back then), hence it'd bond with that. (This is why that "natural performance enhancer" link is Sodium D-Aspartate too. Simply because it'd need to be soluble to be ingested and transported, they toss some Sodium Chloride (salt) in there and voila, soluble D-Aspartate.)
Or D-ornithine being more prone to hydrogen bonds than L-ornithine?
Example, D-Ornithine dihydrochloride, this is achieved through hydrogen bridges, while L-Ornithine can sustain a single hydrochloride molecule through this manner, dihydrochloride is far less stable. (That's not to say D-Ornithine dihydrochloride is very common either, but at least it'd be more potent in demobilizing the ammonia)
I'm no expert either, but I see no reason something like solubility should be dependent on chirality. Wouldn't the solute have to be chiral as well?
Just what the sites regarding these amino acids say, D-Asparte has a solubility of "approximately 0.8 grams per 220mL" (about 3.6 grams per Liter) while L-Asparte is at 4 grams per Liter. Neither have a very high solubility, but the relative difference is still pretty high, and even if it wouldn't bond with sodium and somehow be excreted through the same manner, it would maintain its testostorone production increasing properties.
Then again, these dextro-amino acids aren't exactly common, and the things I'm discussing here haven't been experimented with to great enough extents to provide purely objective, non-speculative conclusions (pfft, lazy scientists and their lack of affection towards quarian wiminz), but they'd be nice side-effects regardless.