ebi-chebi/ChEBI

should disaccharides be glycosides?

ValWood opened this issue · 3 comments

ValWood commented

Carbohydrates
Robert J. Ouellette, J. David Rawn, in Organic Chemistry Study Guide, 2015
26.8 Disaccharides
Disaccharides are glycosides formed from two monosaccharides that can be either aldoses or ketoses.

For the background discussion see
geneontology/go-ontology#23300
(I don't think you were ever contacted)

amalik01 commented

@ValWood I have contacted a few experts in carbohydrate chemistry and will update you once i hear back from them.

  • 👍1
amalik01 commented

Hi @ValWood,

I contacted Gerard Moss, author of 2-carb (IUPAC recommendations on the nomenclature of carbohydrates - https://iupac.qmul.ac.uk/2carb/). He raised this issue with the carbohydrate group and they do not think that dissacharides are glycosides. They are currently working on a glossary of carbohydrate terms for the gold book and their current revised definition for glycoside is:

glycosides: Mixed acetals resulting from the attachment of a glycosyl group to a non-acyl group RO– [and chalcogen replacements thereof (RS–, RSe–)].

I also read 2-Carb-36.2 (https://iupac.qmul.ac.uk/2carb/36.html) where it states that disaccharides without a free hemiacetal group are named as glycosyl glycosides whereas the ones that have a free hemiacetal group are named as glycosylglycose.

ValWood commented

Thanks, we will update the GO definition of Glycoside to match this one.

Just to confirm, doe s this mean that some disaccharides are glycoside, but not all disaccharides are glycosides?