4 ms·

One thing that I always wonder about with these sorts of things is the extent to which chirality comes into play. Biological chemistry generally expresses stro

by yarg 8y ago

One thing that I always wonder about with these sorts of things is the extent to which chirality comes into play. Biological chemistry generally expresses strong chirality biases that do not result from inorganic reactions - but the chirality plays a huge role in terms of how organisms react to the chemicals. If you can control the ratios of a chiral compound's enantiomers then it really is as simple as they say - just a number of compounds thrown together in appropriate ratios; but if not, it will be impossible to truly replicate the results of the standard process.

FavouriteColour 8y ago
Wikipedia says: l-forms of amino acids tend to be tasteless, whereas d-forms tend to taste sweet.[7] Spearmint leaves contain the l-enantiomer of the chemical carvone or R-(−)-carvone and caraway seeds contain the d-enantiomer or S-(+)-carvone.[10] These smell different to most people because our olfactory receptors are chiral. https://en.wikipedia.org/wiki/Chirality_(chemistry)#In_biochemistry https://en.wikipedia.org/wiki/Chirality_(chemistry)#In_bioch...
dnautics 8y ago
an interesting chirality story: The navy contracted John Frost [0] to make rocket fuel biologically. The normal route to butanetriol (the precursor to butanetrioltrinitrate, BTTN, the rocket fuel in sidewinder missiles) is via reduction of malic acid. In order to do this one must consume large quantities of boron, not terribly hard to obtain in the southwestern US, but the problem is that the partially oxidized borate salts are a bitch to clean up and quite toxic - I guess the Navy wanted a greener way to kill people. A biological route would make the entire process cleaner, and less costly. The big problem, is of course, that 1,2,4 butanetriol is very much chiral. You might think that because it's gonna basically be burned who cares anyways, but actually since BTTN is a solid rocket propellant, having a different crystal symmetry can cause potentially undesired propellant effects in the bulk. We can't have a rocket that doesn't work, or perhaps worse, occasionally blows up, on the tarmac because of a teeny tiny difference in solid packing geometries. So Frost had to build two biochemical pathways to the compound. Which he did (btw that is no small feat). The plan was to then combine them 1:1 before subjecting the product to nitration. Then, just for S&G, they took one enantiomer and nitrated it. Turns out the nitration reaction is harsh enough to quantitatively racemize the compound. [0] https://patents.google.com/patent/US7923226B2/en https://patents.google.com/patent/US7923226B2/en In general, if I were doing biosynthesis for profit, I would probably not want to make anything that didn't have a value-add due to the chiral selectivity.

by yarg 8y ago

FavouriteColour 8y ago

Wikipedia says: l-forms of amino acids tend to be tasteless, whereas d-forms tend to taste sweet.[7] Spearmint leaves contain the l-enantiomer of the chemical carvone or R-(−)-carvone and caraway seeds contain the d-enantiomer or S-(+)-carvone.[10] These smell different to most people because our olfactory receptors are chiral. https://en.wikipedia.org/wiki/Chirality_(chemistry)#In_biochemistry https://en.wikipedia.org/wiki/Chirality_(chemistry)#In_bioch...

dnautics 8y ago

an interesting chirality story: The navy contracted John Frost [0] to make rocket fuel biologically. The normal route to butanetriol (the precursor to butanetrioltrinitrate, BTTN, the rocket fuel in sidewinder missiles) is via reduction of malic acid. In order to do this one must consume large quantities of boron, not terribly hard to obtain in the southwestern US, but the problem is that the partially oxidized borate salts are a bitch to clean up and quite toxic - I guess the Navy wanted a greener way to kill people. A biological route would make the entire process cleaner, and less costly. The big problem, is of course, that 1,2,4 butanetriol is very much chiral. You might think that because it's gonna basically be burned who cares anyways, but actually since BTTN is a solid rocket propellant, having a different crystal symmetry can cause potentially undesired propellant effects in the bulk. We can't have a rocket that doesn't work, or perhaps worse, occasionally blows up, on the tarmac because of a teeny tiny difference in solid packing geometries. So Frost had to build two biochemical pathways to the compound. Which he did (btw that is no small feat). The plan was to then combine them 1:1 before subjecting the product to nitration. Then, just for S&G, they took one enantiomer and nitrated it. Turns out the nitration reaction is harsh enough to quantitatively racemize the compound. [0] https://patents.google.com/patent/US7923226B2/en https://patents.google.com/patent/US7923226B2/en In general, if I were doing biosynthesis for profit, I would probably not want to make anything that didn't have a value-add due to the chiral selectivity.