🧵 Mutarotation of glucose
Anonymous at Sun, 23 Jun 2024 21:29:45 UTC No. 16249912
My retarded ass can't comprehend the mutarotation of glucose even if my life depended on it. I can't understand it reading from books, internet or even chatgpt. You retards are my only hope.
>mutarotation is the variation of the capability of glucose to rotate polarized light
Is this variation due simply to the alpha and beta configurations of the closed form of glucose, or do the L and D configurations of the linear molecule also have something to do with it?
I guess what I'm trying to ask is:
>a-glucose <-> D-glucose <-> L-glucose <-> b-glucose
or
>a-glucose <-> D-glucose <-> b-glucose
Anonymous at Mon, 24 Jun 2024 04:39:10 UTC No. 16250367
>>16249912
You dont understand chirality if you think D sugar can transform into L sugar. Since carbinyl group is flat you can get both R and S configurstions of hemiacetals, usually with one being favored due to anomeric effect or equatorial conformation. But every chiral center in a sugar molecule cannot change its chirality on its own, and to go from D to L you'd have to change every chiral center. Mutarotation is purely the result of flat carbonyl group being attacked by nucleophilic hudroxyl group from both sides, and dynamically opening and closing the hemiacetal ring. Linear form is very scarce, hence you can practically ignore it
Anonymous at Mon, 24 Jun 2024 14:47:03 UTC No. 16250886
>>16250367
SHit you're right, changing D to L would require energy to break the bond. Thanks brother
Anonymous at Mon, 24 Jun 2024 17:39:05 UTC No. 16251121
Based thread. Finally some actual fucking chemistry discussed
Anonymous at Mon, 24 Jun 2024 18:06:13 UTC No. 16251179
>>16249912
Beyond what >>16250367 has already said, yes, the alpha and beta forms of D-Glucose have different specific rotation (i.e. they rotate polarized light by different strengths). The linear form would have yet another specific rotation but it is only present in traces, we can mostly ignore it.
>>16250886
Well, bonds being broken and energy being required is more or less intrinsic to every chemical reaction. Even the mutarotation involves breaking bonds. But the path is quite low in activation energy. The key point is that to go from a D- to an L-sugar requires inversion of every stereocenter (as has been said already). And these other stereocenters are just not set up for easy scrambling in glucose (and pretty much all other sugars).