There has been (relatively) recently published a paper ( https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0219008 ), where they claim they found QTL for ratio between two glucosides of the same molecule (trans-zeatin, adenine derivative https://en.wikipedia.org/wiki/Zeatin ).

They claim that unknown (indeed) isomerase could be responsible for that (p. 12, the last paragraph). Now I could imagine other ways to achieve that, but I'm wondering. Are there any isomerases known to transfer sugar molecules?

I'd say they would need to belong to EC group 5.4.4 or 5.4.99, right?

https://www.qmul.ac.uk/sbcs/iubmb/enzyme/EC5/cont5a.html

https://en.wikipedia.org/wiki/Isomerase#Intramolecular_transferases

But quick look at the entries doesn't seem to include any such enzyme. Of course, not all enzymes have EC numbers.

So would you know about any such enzyme?