My first question concerns lupinic acid - conjugate of adenine derivative with alanine

https://commons.wikimedia.org/wiki/File:Lupinic_acid.svg

The question: What type of bond is it between the Ade and Ala?

Is it glycosidic bond? Because the compound is actually synthesised from (O-acetyl)serine, so there is hydroxyl going away (only it's in the form of acetate):

http://www.sbcs.qmul.ac.uk/iubmb/enzyme/EC2/5/1/50.html

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My second question is, whether there are any enzymes known to hydrolyze adenine N9-glucoside (or derivatives/similar compounds)?

I assume they would belong to the EC 3.2.2 subsubclass, right? But in the list of enzymes, I see mostly nucleosidases, if I haven't missed anything.

http://www.sbcs.qmul.ac.uk/iubmb/enzyme/EC3/2/2/

Thank you